A post-processing thermal management device and method using an intake throttle valve and an exhaust throttle valve to work together

Abstract

The present invention discloses a post-processing thermal management device and method that utilizes the combined action of an intake throttle valve and an exhaust throttle valve. The method comprises: the ECU acquiring, in real time, the SCR upstream temperature T measured by the SCR temperature sensor and the DOC upstream temperature measured by the DOC temperature sensor; in a non-DPF regeneration mode, after a set time, the ECU's comparison unit determines whether the SCR upstream temperature T is less than the target temperature T1; in response to the determination that the SCR upstream temperature T is less than the target temperature T1, the control unit controls the openings of the intake throttle valve and the exhaust throttle valve through a first program to rapidly increase the exhaust temperature. The present invention has the characteristics of DOC+DPF+SCR post-processing, providing different management strategies for different exhaust temperatures and different modes. While not affecting the driving dynamics experience, the intake throttle valve and the exhaust throttle valve act simultaneously, and the reasonable setting of the openings allows the exhaust temperature to be rapidly increased in a short period of time.

Description

Technical Field

[0001] The present invention relates to the field of aftertreatment thermal management of engines, and specifically to an aftertreatment thermal management device and method that act jointly through an intake throttle valve and an exhaust throttle valve. Background Art

[0002] The exhaust throttle valve is used for the control of exhaust temperature management. When the acquired temperature value is not greater than the preset temperature, it issues a demand for exhaust temperature management, and restores the normal opening of the exhaust throttle valve when the temperature is greater than the preset temperature. It is found during use that relying only on the action of the exhaust throttle valve, if the exhaust throttle valve is closed slightly, the exhaust volume in the small load area is small and the effect of increasing the exhaust temperature is not obvious. If the exhaust throttle valve is closed largely, the exhaust is not smooth, resulting in a longer residence time of the mixture in the cylinder, an increase in NOx emissions, and an impact on the engine power performance. Summary of the Invention

[0003] The purpose of the present invention is to provide an aftertreatment thermal management device and method that act jointly through an intake throttle valve and an exhaust throttle valve. According to the characteristics of DOC+DPF+SCR aftertreatment, different management strategies are provided for different exhaust temperatures and different modes. While not affecting the driving power experience, by the simultaneous action of the intake throttle valve and the exhaust throttle valve, the opening is reasonably set to rapidly increase the exhaust temperature in a short time.

[0004] To solve the above technical problems, an aftertreatment thermal management device that acts jointly through an intake throttle valve and an exhaust throttle valve includes an intake throttle valve connected to the engine intake pipe and an exhaust throttle valve connected to the engine exhaust pipe. The engine exhaust pipe is sequentially connected with a DOC, a DPF, and an SCR along the exhaust direction. The engine is connected to an ECU. DOC temperature sensors, DPF temperature sensors, and SCR temperature sensors electrically connected to the ECU are respectively provided upstream of the DOC, DPF, and SCR. The ECU is also electrically connected to a timer and a regeneration request switch. Its structural feature is that a comparison unit and a control unit electrically connected to the comparison unit are provided in the ECU. The control unit controls the opening of the intake throttle valve and the exhaust throttle valve by receiving the signal of the comparison unit. Target temperatures T1, T2, and T3 upstream of the SCR, where T1<T2<T3, and the high-efficiency region temperature upstream of the DOC are preset in the comparison unit.

[0005] Further, the intake throttle valve is a mechanical throttle valve, including a body, a throttle position sensor, and a stepper motor.

[0006] Further, the intake throttle valve is an electronic throttle valve, including a body, a throttle position sensor, and a DC motor.

[0007] To solve the above technical problems, a post-processing thermal management method using the combined action of an intake throttle valve and an exhaust throttle valve is provided, using any of the above-mentioned post-processing thermal management devices using the combined action of an intake throttle valve and an exhaust throttle valve, and is characterized by comprising the following steps:

[0008] S10: The ECU acquires in real time the SCR upstream temperature T measured by the SCR temperature sensor and the DOC upstream temperature measured by the DOC temperature sensor;

[0009] S20: In the non-DPF regeneration mode, after a set time, the comparison unit of the ECU determines whether the SCR upstream temperature T is less than the target temperature T1;

[0010] In response to a determination that the SCR upstream temperature T is less than the target temperature T1, the control unit controls the openings of the intake throttle valve and the exhaust throttle valve through a first program to quickly increase the exhaust temperature;

[0011] In response to a determination result that the SCR upstream temperature T is not less than the target temperature T1, the comparison unit of the ECU determines whether the SCR upstream temperature is less than the target temperature T2;

[0012] In response to a determination that the SCR upstream temperature T is lower than the target temperature T2, the control unit controls the openings of the exhaust throttle valve and the intake throttle valve through a second program until the SCR upstream temperature T is higher than the target temperature T3, and the control unit controls the exhaust throttle valve and the intake throttle valve to be fully opened.

[0013] S30: In the DPF regeneration mode, the control unit controls the intake throttle valve and the exhaust throttle valve to reasonably and intelligently adjust their openings until the DOC upstream temperature reaches the high-efficiency area temperature.

[0014] Furthermore, under the first program, the intake throttle valve and the exhaust throttle valve intelligently adjust their openings simultaneously.

[0015] Furthermore, the intelligent adjustment method of the intake throttle valve and the exhaust throttle valve is: the exhaust throttle valve adjusts the opening of the exhaust throttle valve through the open-loop output value of the speed and oil valve opening preset in the ECU, and the intake throttle valve adjusts the opening of the exhaust throttle valve through the closed-loop control of the speed, oil, and intake pressure preset in the ECU.

[0016] Furthermore, the speed-fuel-valve-opening map curve is drawn based on a data table of engine speed, fuel injection quantity and valve opening.

[0017] Further, the rotational speed - fuel quantity - intake pressure MAP is drawn based on the data table of the engine's rotational speed, fuel injection quantity, and intake pressure to obtain a MAP curve.

[0018] Further, in the second program, the exhaust throttle valve is fully open, and the intake throttle valve is closed - loop controlled to adjust the opening degree.

[0019] Further, after the regeneration is completed, the control unit controls the intake throttle valve and the exhaust throttle valve to return to the non - DPF regeneration mode.

[0020] After adopting the above - mentioned device and method, according to different temperatures, the control unit reasonably controls the opening degrees of the intake throttle valve and the exhaust throttle valve. Through their combined action, the exhaust gas temperature is efficiently increased, thus solving the post - treatment problems caused by low temperature (difficult ignition of DOC, short DPF regeneration cycle, easy crystallization of SCR). Compared with the traditional method that only relies on the action of the exhaust throttle valve, it can quickly increase the exhaust gas temperature, avoid the problem that the mixed gas stays in the cylinder for a long time due to poor exhaust, resulting in an increase in NOx emissions and an impact on engine performance. After the engine's cold start, the temperature T upstream of the SCR is close to the ambient temperature, that is, lower than the target temperature T1. At this time, the control unit controls the opening degrees of the intake throttle valve and the exhaust throttle valve through the first program, so that the temperature T upstream of the SCR rises to the target temperature T1 in a very short time. At this temperature, urea is normally injected and the crystallization risk is small. When the engine runs at a low load for a long time, T1 < T < T2. Within this temperature range, the DPF has no passive regeneration to remove carbon. The intake throttle valve adjusts the opening degree to increase the temperature T upstream of the SCR to T3, and the DPF has passive regeneration to remove carbon. Description of the Drawings

[0021] Figure 1 This is a flowchart of the post - treatment thermal management method of the present invention through the combined action of the intake throttle valve and the exhaust throttle valve. Detailed Embodiments

[0022] Refer to Figure 1, the post-treatment thermal management device that works together with the intake throttle valve and the exhaust throttle valve includes an intake throttle valve connected to the engine intake pipe and an exhaust throttle valve connected to the engine exhaust pipe. Along the exhaust direction on the engine exhaust pipe, a DOC, a DPF, and an SCR are sequentially connected. The engine is connected to an ECU. DOC temperature sensors, DPF temperature sensors, and SCR temperature sensors electrically connected to the ECU are respectively provided upstream of the DOC, the DPF, and the SCR. The ECU is also electrically connected to a timer and a regeneration request switch. A comparison unit and a control unit electrically connected to the comparison unit are provided in the ECU. The control unit controls the opening degrees of the intake throttle valve and the exhaust throttle valve by receiving signals from the comparison unit. The intake throttle valve can be a mechanical throttle valve, which specifically includes a body, a throttle position sensor, and a stepper motor. During use, the pedal pulls the snap ring on the mechanical throttle valve body through a metal wire to push the valve disc of the valve throat of the valve body, thereby controlling the intake air volume of the engine. Preferably, the intake throttle valve is an electronic throttle valve, which includes a body, a throttle position sensor, and a DC motor. During use, the throttle position sensor detects the opening degree of the valve disc and transmits it to the ECU. The control unit of the ECU drives the DC motor to control the valve disc, so that the intake air volume meets the control requirements. The above-mentioned mechanical throttle valve and electronic throttle valve are both prior arts.

[0023] In the comparison unit, a target temperature T1 (generally taken as 225°C - 235°C, preferably taken as 230°C), T2 (generally taken as 245°C - 255°C, preferably taken as 250°C), and T3 (generally taken as 295°C - 305°C, preferably taken as 300°C) upstream of the SCR are preset, and T1 < T2 < T3, and the high-efficiency region temperature (usually 300 - 400°C) upstream of the DOC.

[0024] A post-treatment thermal management method that works together with the intake throttle valve and the exhaust throttle valve, using the post-treatment thermal management device that works together with the intake throttle valve and the exhaust throttle valve described in any one of the above, includes the following steps:

[0025] S10: The ECU real-time obtains the temperature T upstream of the SCR measured by the SCR temperature sensor and the temperature upstream of the DOC measured by the DOC temperature sensor.

[0026] S20: In the non-DPF regeneration mode, after a set time (generally taken as 0.8h - 1.2h, preferably taken as 1h), the comparison unit of the ECU determines whether the temperature T upstream of the SCR is less than the target temperature T1.

[0027] In response to a determination that the SCR upstream temperature T is less than the target temperature T1, the control unit controls the openings of the intake throttle valve and the exhaust throttle valve through a first program to rapidly increase the exhaust temperature and rapidly raise the SCR upstream temperature T to the target temperature T1. The first program specifically refers to the control unit controlling the intake throttle valve and the exhaust throttle valve to intelligently adjust their openings simultaneously. The intelligent adjustment method for the intake throttle valve and the exhaust throttle valve is as follows: the exhaust throttle valve adjusts its opening in an open loop using a speed and fuel valve opening Maipu output value preset in the ECU. Specifically, the speed and fuel valve opening Maipu is a map curve drawn based on a data table of engine speed, fuel injection amount, and valve opening. The map curve can be drawn using MATLAB, where X represents speed, Y represents fuel injection amount, and Z represents valve opening. The intake throttle valve adjusts its opening through a closed-loop control of the speed, oil volume, and intake pressure preset in the ECU. Specifically, the speed, oil volume, and intake pressure Maipu are based on a data table of engine speed, fuel injection volume, and intake pressure to draw a map curve. The map curve can be drawn using MATLAB, where X represents speed, Y represents fuel injection volume, and Z represents intake pressure. This thermal management mode ensures that the exhaust temperature rises rapidly, urea is injected as quickly as possible, and the risk of urea crystallization is minimized.

[0028] In response to a determination result that the SCR upstream temperature T is not less than the target temperature T1, the comparison unit of the ECU determines whether the SCR upstream temperature is less than the target temperature T2;

[0029] In response to a determination that the SCR upstream temperature T is less than the target temperature T2, the control unit controls the openings of the exhaust throttle valve and the intake throttle valve through a second procedure. Specifically, the second procedure involves the control unit controlling the exhaust throttle valve to fully open and the intake throttle valve to adjust its opening through closed-loop control. Within this temperature range, the DPF does not passively regenerate and decarbonize. Until the SCR upstream temperature T exceeds the target temperature T3, the control unit controls the exhaust throttle valve and the intake throttle valve to fully open, ensuring optimal engine economy.

[0030] S30: In the DPF regeneration mode, the control unit controls the intake throttle valve and the exhaust throttle valve to reasonably and intelligently adjust their openings until the DOC upstream temperature reaches the high-efficiency zone temperature. At this temperature, the DPF regeneration cycle is short.

[0031] After the regeneration is completed, the control unit controls the intake throttle valve and the exhaust throttle valve to return to the non-DPF regeneration mode.

[0032] After the engine is started from a cold state, the temperature T upstream of the SCR is close to the ambient temperature and lower than the target temperature T1. At this time, the control unit controls the opening of the intake throttle valve and the exhaust throttle valve through the first program to quickly increase the exhaust temperature, so that the temperature T upstream of the SCR is quickly raised to the target temperature T1. At this temperature, urea is normally injected and the risk of crystallization is relatively low. This avoids the following problems when relying solely on the exhaust throttle valve. For example, if the exhaust throttle valve is closed slightly, the exhaust volume in the low-load area is small and the effect of raising the exhaust temperature is not obvious. If the exhaust throttle valve is closed widely, the exhaust is not smooth, causing the mixture to stay in the cylinder for a long time, increasing NOx emissions and affecting the engine's power. When the engine runs at low load for a long time, T1

Claims

1. A post-processing thermal management method using a combined action of an intake throttle valve and an exhaust throttle valve, using a post-processing thermal management device using a combined action of an intake throttle valve and an exhaust throttle valve, characterized in that: The post-treatment thermal management device includes an intake throttle valve connected to the engine intake pipe and an exhaust throttle valve connected to the engine exhaust pipe. The engine exhaust pipe is sequentially connected with a DOC, a DPF, and an SCR along the exhaust direction. The engine is connected to an ECU. DOC temperature sensors, DPF temperature sensors, and SCR temperature sensors electrically connected to the ECU are respectively provided upstream of the DOC, the DPF, and the SCR. The ECU is also electrically connected to a timer and a regeneration request switch. It is characterized in that: a comparison unit and a control unit electrically connected to the comparison unit are provided in the ECU. The control unit controls the opening degrees of the intake throttle valve and the exhaust throttle valve by receiving signals from the comparison unit. Target temperatures T1, T2, and T3 upstream of the SCR, where T1 < T2 < T3, and the high-efficiency region temperature upstream of the DOC are preset in the comparison unit. The intake throttle valve is a mechanical throttle valve, including a body, a throttle position sensor, and a stepper motor. The intake throttle valve is an electronic throttle valve, including a body, a throttle position sensor, and a DC motor. And it includes the following steps: S10: The ECU obtains in real time the temperature T upstream of the SCR measured by the SCR temperature sensor and the temperature upstream of the DOC measured by the DOC temperature sensor. S20: In the non-DPF regeneration mode, after a set time, the comparison unit of the ECU determines whether the temperature T upstream of the SCR is less than the target temperature T1. In response to the determination result that the temperature T upstream of the SCR is less than the target temperature T1, the control unit controls the opening degrees of the intake throttle valve and the exhaust throttle valve through a first program to rapidly increase the exhaust temperature. In response to the determination result that the temperature T upstream of the SCR is not less than the target temperature T1, the comparison unit of the ECU determines whether the temperature upstream of the SCR is less than the target temperature T2. In response to the determination result that the temperature T upstream of the SCR is less than the target temperature T2, the control unit controls the opening degrees of the exhaust throttle valve and the intake throttle valve through a second program until the temperature T upstream of the SCR is higher than the target temperature T3, and the control unit controls the exhaust throttle valve and the intake throttle valve to be adjusted to the fully open position. S30: In the DPF regeneration mode, the control unit controls the intake throttle valve and the exhaust throttle valve to reasonably and intelligently adjust the opening degrees until the temperature upstream of the DOC reaches the high-efficiency region temperature.

2. The post-processing thermal management method using the combined action of an intake throttle valve and an exhaust throttle valve according to claim 1, characterized in that: In the first program, the intake throttle valve and the exhaust throttle valve simultaneously and intelligently adjust the opening degrees.

3. The post-processing thermal management method using the combined action of an intake throttle valve and an exhaust throttle valve according to claim 2, wherein: The intelligent adjustment method of the intake throttle valve and the exhaust throttle valve is: the exhaust throttle valve adjusts the opening degree by an open-loop output value of the speed fuel valve opening map preset in the ECU, and the intake throttle valve adjusts the opening degree by a closed-loop control of the speed fuel intake pressure map preset in the ECU.

4. The post-processing thermal management method using the combined action of an intake throttle valve and an exhaust throttle valve according to claim 3 is characterized by: The speed fuel valve opening map is drawn based on the data table of the engine speed, fuel injection amount, and valve opening degree.

5. The post-processing thermal management method through the combined action of an intake throttle valve and an exhaust throttle valve according to claim 3 is characterized by: The speed, fuel injection amount and intake pressure map curve is drawn based on the data table of engine speed, fuel injection amount and intake pressure.

6. The post-processing thermal management method through the combined action of an intake throttle valve and an exhaust throttle valve according to claim 1, characterized in that: In the second program, the exhaust throttle valve is fully opened, and the intake throttle valve is closed-loop controlled to adjust the opening.

7. The post-processing thermal management method through the combined action of an intake throttle valve and an exhaust throttle valve according to claim 1, characterized in that: After the regeneration is completed, the control unit controls the intake throttle valve and the exhaust throttle valve to return to the non-DPF regeneration mode.

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