A Method for Exhaust Gas Heating of an On-vehicle Exhaust Gas Detection Device

Abstract

The present invention provides a tail gas heating method for an in-vehicle tail gas detection device, which comprises the following steps: Step S1, detecting the external environment temperature through a first temperature sensor and sending the environmental temperature signal to a heating controller; Step S2, detecting the tail gas temperature through a second temperature sensor and sending the tail gas temperature signal to the heating controller; Step S3, the heating controller adjusts the initial heating power of the heating device in the tail gas connection pipeline in real time according to the external environment temperature and the tail gas temperature, so that the initial heating power decreases as the external environment temperature and the tail gas temperature increase, and increases as the external environment temperature and the tail gas temperature decrease. The present invention can ensure the test accuracy and save energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle exhaust gas detection, and particularly relates to an exhaust gas heating method for an on-vehicle exhaust gas detection device. Background Art

[0002] The requirements of the actual road emission test are introduced in the light vehicle national VI regulations to monitor the emission level during the actual driving process of the vehicle, covering altitudes below 2400 m and environmental temperatures from -7 degrees to 35 degrees. Currently, when conducting the actual road emission test on light vehicles, an on-vehicle exhaust gas detection device (abbreviated as PEMS device) is generally used to measure the vehicle exhaust emissions in real time. The PEMS device is connected to the tail end of the vehicle exhaust through an exhaust gas connection pipeline to measure the vehicle exhaust emissions. However, in a low-temperature environment, due to the low temperature of the vehicle exhaust tail pipe and the presence of moisture in the exhaust gas, water is easily formed in the pipeline of the PEMS device after cooling, affecting the accuracy of the emission test and the service life of the consumables.

[0003] In the prior art, heating wires are usually added to the exhaust gas connection pipeline connecting the PEMS device and the vehicle tail pipe, and after the PEMS device is turned on, the exhaust gas in the exhaust gas connection pipeline is heated at a constant power. However, this method is prone to the problem of insufficient heating power in a low-temperature environment, resulting in the accumulation of moisture in the tail pipe; and overheating in a high-temperature environment, leading to increased energy consumption and energy waste. Therefore, how to avoid the problems of insufficient heating power in a low-temperature environment and overheating in a high-temperature environment has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] The purpose of the present invention is to provide an exhaust gas heating method for an on-vehicle exhaust gas detection device to solve the above technical problems in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] An exhaust gas heating method for an on-vehicle exhaust gas detection device, which includes the following steps:

[0007] Step S1: Detect the external environment temperature through a first temperature sensor and send the environmental temperature signal to the heating controller;

[0008] Step S2: Detect the exhaust gas temperature through a second temperature sensor and send the exhaust gas temperature signal to the heating controller;

[0009] Step S3: The heating controller adjusts the initial heating power of the heating device in the exhaust gas connection pipeline in real time according to the external environment temperature and the exhaust gas temperature, so that the initial heating power decreases as the external environment temperature and the exhaust gas temperature increase, and increases as the external environment temperature and the exhaust gas temperature decrease.

[0010] Preferably, a first correction coefficient for correcting the initial heating power is set in the heating controller, so that the heating power control value output by the heating controller to the heating device is: initial heating power × first correction coefficient; the first correction coefficient is positively related to the exhaust gas flow rate.

[0011] Preferably, as the exhaust gas flow rate increases, the value of the first correction coefficient gradually rises from 0.85 to 1.

[0012] Preferably, a second correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient; the second correction coefficient is positively related to the external environmental humidity.

[0013] Preferably, as the external environmental humidity increases, the value of the second correction coefficient gradually rises from 0.2 to 0.5.

[0014] Preferably, a third correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient + third correction coefficient; the third correction coefficient is positively related to the external atmospheric pressure.

[0015] Preferably, as the external atmospheric pressure rises, the value of the third correction coefficient gradually rises from 0.3 to 0.5.

[0016] Preferably, the external environmental humidity and the external atmospheric pressure are obtained through a humidity sensor and a pressure sensor provided on the vehicle-mounted exhaust gas detection device respectively.

[0017] The beneficial effects of the present invention are as follows:

[0018] For the exhaust gas heating method of the vehicle-mounted exhaust gas detection device of the present invention, its heating controller can adjust the initial heating power of the heating device in the exhaust gas connection pipeline in real time according to the external environmental temperature and the exhaust gas temperature, so that the initial heating power decreases as the external environmental temperature and the exhaust gas temperature increase, and increases as the external environmental temperature and the exhaust gas temperature decrease. Thus, it can ensure that in a low-temperature environment, the heating device has sufficient heating power to effectively reduce the moisture in the exhaust gas, so that there is no easy accumulation of water in the pipeline of the vehicle-mounted exhaust gas detection device, ensuring the test accuracy; at the same time, it can ensure that in a high-temperature environment, the heating power is small to avoid overheating, thereby effectively reducing energy consumption and better avoiding energy waste. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments, and will further elaborate on the specific embodiments of the present invention in combination with the drawings. Among them

[0020] Figure 1 It is a flowchart of the exhaust gas heating method for the vehicle-mounted exhaust gas detection device provided by the embodiment of the present invention. Specific embodiments

[0021] To enable those skilled in the art to better understand the technical solutions of the present invention, the following will further elaborate on this solution in combination with specific embodiments.

[0022] As Figure 1 shown, the embodiment of the present invention provides an exhaust gas heating method for a vehicle-mounted exhaust gas detection device, which includes the following steps:

[0023] Step S1: Detect the external environmental temperature through the first temperature sensor and send the environmental temperature signal to the heating controller;

[0024] Step S2: Detect the exhaust gas temperature through the second temperature sensor and send the exhaust gas temperature signal to the heating controller;

[0025] Step S3: The heating controller adjusts the initial heating power of the heating device in the exhaust gas connection pipeline in real time according to the external environmental temperature and the exhaust gas temperature, so that the initial heating power decreases as the external environmental temperature and the exhaust gas temperature increase, and increases as the external environmental temperature and the exhaust gas temperature decrease.

[0026] For the exhaust gas heating method for the vehicle-mounted exhaust gas detection device provided by the embodiment of the present invention, its heating controller can adjust the initial heating power of the heating device in the exhaust gas connection pipeline in real time according to the external environmental temperature and the exhaust gas temperature, so that the initial heating power decreases as the external environmental temperature and the exhaust gas temperature increase, and increases as the external environmental temperature and the exhaust gas temperature decrease. Thus, it can ensure that in a low-temperature environment, the heating device has sufficient heating power to effectively reduce the moisture in the exhaust gas, so that there is no easy accumulation of water in the pipeline of the vehicle-mounted exhaust gas detection device; at the same time, it can ensure that in a high-temperature environment, the heating power is small, avoiding overheating, thereby effectively reducing energy consumption and better avoiding energy waste.

[0027] Furthermore, a first correction coefficient for correcting the initial heating power is set in the heating controller, so that the heating power control value output by the heating controller to the heating device is: initial heating power × first correction coefficient; this first correction coefficient is positively related to the exhaust gas flow rate. With this solution, when setting the control value, the exhaust gas flow rate factor is considered, and the initial heating power is corrected using the first correction coefficient that is positively correlated with the exhaust gas flow rate, so that after the heating device outputs power according to this control value, a better energy-saving effect can be achieved, and at the same time, it can be ensured that there is less moisture in the exhaust gas and it is not easy to have water accumulation in the PEMS device.

[0028] Specifically, as the exhaust gas flow rate increases, the value of the first correction coefficient gradually rises from 0.85 to 1. It can be understood that when the exhaust gas flow rate is large, due to the fast air flow speed, the value of the first correction coefficient at this time will be large; conversely, when the exhaust gas flow rate is small, due to the slow air flow speed, the value of the first correction coefficient at this time will be small. The first correction coefficient can be denoted as A1. In one embodiment, the specific values of the first correction coefficient are shown in Table 1.

[0029] Table 1 Specific values of the first correction coefficient

[0030]

[0031] Furthermore, a second correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient; this second correction coefficient is positively related to the external environmental humidity. With this solution, the external environmental humidity factor is considered when calculating the control value, and the control value is corrected using the second correction coefficient that is positively correlated with the external environmental humidity, so that after the heating device outputs power according to this control value, a better energy-saving effect can be achieved, and the exhaust gas can be heated sufficiently, that is, there is less or no moisture in the exhaust gas, so that it is not easy to have water accumulation in the PEMS device.

[0032] Specifically, as the external environmental humidity increases, the value of the second correction coefficient gradually rises from 0.2 to 0.5. It can be understood that when the external environmental humidity is large, the value of the second correction coefficient is large; when the external environmental humidity is small, the value of the second correction coefficient is small.

[0033] The second correction coefficient can be denoted as A2. In one embodiment, the specific values of the second correction coefficient are shown in Table 2. When the external environmental humidity is less than 10%, the second correction coefficient is 0.2; when the external environmental humidity is greater than 90%, the second correction coefficient is 0.5.

[0034] Table 2 Specific values of the second correction coefficient

[0035] External environmental humidity 10％ 30％ 50％ 70％ 90％ <![CDATA[A2]]> 0.2 0.2 0.3 0.4 0.5

[0036] Further, a third correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient + third correction coefficient; the third correction coefficient is positively related to the external atmospheric pressure. With this solution, the external atmospheric pressure factor is also considered when calculating the control value, and the control value is further corrected by using the third correction coefficient that is positively correlated with the external atmospheric pressure, so that after the heating device outputs power according to the control value, it has a good energy-saving effect, and at the same time, the tail gas is heated sufficiently to eliminate the moisture in the tail gas, so that when the tail gas enters the PEMS device, it is not easy to have a water accumulation phenomenon in the device.

[0037] It can be understood that the initial heating power can be denoted as P1, the heating power control value can be denoted as P, the third correction coefficient can be denoted as A3, and combined with the above-mentioned first correction coefficient denoted as A1 and the second correction coefficient denoted as A2, then P = P1×A1 + A2 + A3.

[0038] Specifically, as the external atmospheric pressure increases, the value of the third correction coefficient gradually rises from 0.3 to 0.5. It can be understood that when the external atmospheric pressure is small, the value of the third correction coefficient is small; conversely, when the external atmospheric pressure is large, the value of the third correction coefficient is large.

[0039] In an embodiment, the specific values of the third correction coefficient are shown in Table 3. When the external atmospheric pressure is less than 76 Kpa, the second correction coefficient is 0.3; when the external environmental humidity is greater than 100 Kpa, the second correction coefficient is 0.5.

[0040] Table 3 Specific values of the third correction coefficient

[0041] External atmospheric pressure (Kpa) 76 87 93 100 <![CDATA[A3]]> 0.3 0.3 0.4 0.5

[0042] Preferably, the external environmental humidity and the external atmospheric pressure are obtained through a humidity sensor and a pressure sensor respectively, which are arranged on the vehicle exhaust gas detection device. It can be understood that the humidity sensor is used to detect the external environmental humidity and send a humidity signal to the heating controller, so that the heating controller can adjust the second correction coefficient in real time according to the external environmental humidity; the pressure sensor is used to detect the external atmospheric pressure and send an atmospheric pressure signal to the heating controller, so that the heating controller can adjust the third correction coefficient in real time according to the external atmospheric pressure. Preferably, the first temperature sensor is arranged on the PEMS device, the second temperature sensor is arranged inside the PEMS device, and a flowmeter for detecting the exhaust gas flow is also arranged on the PEMS device, so that the flowmeter and each sensor are integrated on the PEMS device, making the PEMS device have more functions without installing these sensors on other components. It can be understood that the flowmeter is used to detect the flow of the exhaust gas flowing into the PEMS device and send an exhaust gas flow signal to the heating controller, so that the heating controller can adjust the first correction coefficient in real time according to the exhaust gas flow.

[0043] Specifically, the initial heating power is a two-dimensional table related to the external environmental temperature and the exhaust gas temperature. In a specific embodiment, the specific values of the initial heating power, the external environmental temperature, and the exhaust gas temperature are shown in Table 4. The lower the external environmental temperature, the greater the heating power; the lower the exhaust gas temperature, the greater the heating power. The range of the external environmental temperature is mainly based on the environmental temperature boundary conditions of the actual road emission test (abbreviation: RDE test), and it is set to -10 degrees to 40 degrees; according to the vehicle test and empirical data, the range of the exhaust gas temperature can be -10 degrees to 500 degrees. In Table 4, x represents the exhaust gas temperature and y represents the external environmental temperature.

[0044] Table 4 Relationship table of initial heating power with external environmental temperature and exhaust gas temperature

[0045]

[0046] It can be understood that in Table 4, when the external environmental temperature is relatively high, there is basically no situation where the exhaust gas temperature is relatively low. Therefore, from a practical consideration, when the external environmental temperature is not less than 5 degrees Celsius, there is no case where the exhaust gas temperature is -10 degrees. Therefore, the values of the initial heating power at each point at this time are set to 0; when the exhaust gas temperature is 500 degrees, it is appropriate to reduce the initial heating power so that it operates at a low power to continue eliminating the possible moisture, because there is always moisture in the exhaust gas. Therefore, a certain heating power is also required in a high-temperature environment to eliminate the moisture.

[0047] It can be understood that the heating device provided in the tail gas connection pipeline can be a heating wire or other devices, as long as the device can heat the tail gas in the tail gas connection pipeline; the heating controller can control the output power of the heating device so that the output power of the heating device is equal to the above heating power control value; for safety considerations, referring to the design value of the heating device in the tail gas connection pipeline, the maximum value of the heating power control value is set in the heating controller to ensure better safety of the test. It is preferable that the values of the above initial heating power and correction coefficient are set by combining calibration and empirical values in the chassis dynamometer test and the actual road emission test.

[0048] After the present invention is applied in vehicle testing, according to the actual test results in low-temperature environments, high-temperature environments and high-altitude areas, it is shown that the PEMS device adopting the test method can effectively avoid the problem of water accumulation in the tail gas connection pipeline and the pipeline of the PEMS device, and at the same time avoid excessive heating of the tail gas in high-temperature environments.

[0049] The above are only the preferred embodiments of the present invention. It should be noted that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, after reading the content of the present invention, those skilled in the relevant art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims

1. A method for heating vehicle exhaust gas used in a vehicle exhaust gas detection device, characterized in that, It includes the following steps: Step S1: Detect the external environmental temperature through the first temperature sensor and send the environmental temperature signal to the heating controller; Step S2: Detect the exhaust gas temperature through the second temperature sensor and send the exhaust gas temperature signal to the heating controller; Step S3: The heating controller adjusts the initial heating power of the heating device in the exhaust gas connection pipeline in real time according to the external environmental temperature and the exhaust gas temperature, so that the initial heating power decreases as the external environmental temperature and the exhaust gas temperature increase, and increases as the external environmental temperature and the exhaust gas temperature decrease; A first correction coefficient for correcting the initial heating power is set in the heating controller, so that the heating power control value output by the heating controller to the heating device is: initial heating power × first correction coefficient; this first correction coefficient is positively related to the exhaust gas flow rate; A second correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient; this second correction coefficient is positively related to the external environmental humidity; A third correction coefficient for correcting the heating power control value is also set in the heating controller, so that the heating power control value is: initial heating power × first correction coefficient + second correction coefficient + third correction coefficient; this third correction coefficient is positively related to the external atmospheric pressure.

2. The method for heating vehicle exhaust gas used in a vehicle exhaust gas detection device according to claim 1, characterized in that, As the exhaust gas flow rate increases, the value of the first correction coefficient gradually rises from 0.85 to 1.

3. The method for heating vehicle exhaust gas used in a vehicle exhaust gas detection device according to claim 1, characterized in that, As the external environmental humidity increases, the value of the second correction coefficient gradually rises from 0.2 to 0.

5.

4. The method for heating vehicle exhaust gas used in a vehicle exhaust gas detection device according to claim 1, characterized in that, As the external atmospheric pressure rises, the value of the third correction coefficient gradually rises from 0.3 to 0.

5.

5. The method for heating vehicle exhaust gas used in a vehicle exhaust gas detection device according to claim 1, characterized in that, The external environmental humidity and the external atmospheric pressure are obtained through a humidity sensor and a pressure sensor respectively arranged on the vehicle exhaust gas detection device.

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