Method for improving odor in a vehicle

Abstract

The application provides a method for improving the odor in a vehicle, comprising: S1: using a trapping tube to trap the gas to be tested in the vehicle, using a secondary thermal desorption instrument to desorb, to obtain first desorption gas and second desorption gas; S2: chromatographic separation, mass spectrometric detection and olfactory detection are performed on the first desorption gas; S3: chromatographic separation is performed on the second desorption gas, and the separated tail gas is collected in sections; the tail gas section with the highest matching degree of odor with the gas to be tested in the vehicle is selected, and an odor substance is screened out, which simultaneously satisfies the following conditions: (1) the peak area ratio of the odor substance in the chromatograph is greater than or equal to 5%; (2) the odor threshold of the odor substance is lower than 100 μg / m 3 ; (3) the odor substance is identified by an olfactometer; S4: mixing the odor substance, improving the odor of the mixed gas by adjusting the proportion of the odor substance contained in the mixed gas, and improving the odor in the vehicle based on the adjusted results.

Description

Technical Field

[0001] This application relates to the field of in-vehicle odor analysis, and more particularly to a method for improving in-vehicle odor. Background Technology

[0002] The main source of odor in vehicles is volatile organic compounds (VOCs) released from interior materials and components. As people begin to use vehicle odor as a factor in evaluating vehicle quality, tracing the source of odor and improving it is an urgent technical problem to be solved. Summary of the Invention

[0003] In view of this, this application provides a method for improving in-vehicle odor, comprising: S1: capturing a gas to be tested in the vehicle using a trapping tube to obtain a first captured gas and a second captured gas, and desorbing the first captured gas and the second captured gas using a secondary thermal desorption instrument to obtain a first desorbed gas and a second desorbed gas; S2: performing chromatographic separation, mass spectrometry detection, and odor detection on the first desorbed gas using a gas chromatograph-olfactometer / mass spectrometer, and recording the detection results; S3: performing chromatographic separation on the second desorbed gas, and segmenting the separated exhaust gas. Collect at least two sets of exhaust gas segments; compare the odor of each set of exhaust gas segments with the odor of the gas to be tested in the vehicle, select the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle, and combine the detection results in S2 to screen out odor substances from the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle. The odor substances must meet the following conditions: (1) the peak area ratio of the odor substance relative to the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle is ≥5% in the chromatograph; (2) the odor threshold of the odor substance is lower than 100μg / m 3 (3) Odor substances are identified by the olfactory detector; S4: Mix the odor substances to obtain a mixed gas, verify the odor of the mixed gas, improve the odor of the mixed gas by adjusting the proportion of odor substances contained in the mixed gas, and improve the odor inside the car based on the adjusted results.

[0004] In some embodiments, the trapping tube is sequentially divided into a low-boiling-point substance trapping section, a medium-boiling-point substance trapping section, and a high-boiling-point substance trapping section in the gas inlet direction. The low-boiling-point substance trapping section, the medium-boiling-point substance trapping section, and the high-boiling-point substance trapping section each include a first packing material, a second packing material, and a third packing material, respectively. The secondary thermal desorption device includes a cold trap, which is sequentially divided into a low-boiling-point substance enrichment section, a medium-boiling-point substance enrichment section, and a high-boiling-point substance enrichment section in the gas inlet direction. The packing materials in the low-boiling-point substance enrichment section, the medium-boiling-point substance enrichment section, and the high-boiling-point substance enrichment section are the same as those in the low-boiling-point substance trapping section, the medium-boiling-point substance trapping section, and the high-boiling-point substance trapping section, respectively.

[0005] In some implementations, S3 satisfies the following condition: at least two sets of exhaust gas sections include two to five sets of exhaust gas sections.

[0006] In some implementations, S3 satisfies the following: segmented collection of the separated exhaust gas includes segmented collection of the separated exhaust gas at equal time intervals.

[0007] In some implementations, improving the odor of the gas mixture includes improving odor intensity and flavor profile.

[0008] In some implementations, improving the odor of the gas mixture includes improving the odor intensity.

[0009] In some embodiments, the first filler includes at least one of Carbopack X, Carbograph 5TD, Carboxen 1000, and Tenax TA with a particle size of 60 to 80 mesh.

[0010] In some embodiments, the second filler includes at least one of Carbopack B and Tenax TA with a particle size of 35 to 60 mesh.

[0011] In some implementations, the third filler includes at least one of Tenax GR and Carbopack C.

[0012] In some implementations, the refrigeration temperature corresponding to the low-boiling-point substance enrichment section is -30°C to -20°C.

[0013] In some implementations, the refrigeration temperature corresponding to the enrichment range of medium-boiling-point substances is -20°C to 0°C.

[0014] In some implementations, the refrigeration temperature corresponding to the high-boiling-point substance enrichment section is 0°C to 15°C.

[0015] By using the method for improving in-vehicle odor of this application, odor substances can be identified more efficiently, and the in-vehicle odor can be improved. Attached Figure Description

[0016] Figure 1 This is a flowchart of a method for improving in-vehicle odor according to an embodiment of this application; Figure 2 This is the chromatographic measurement result of the first desorbed gas according to an embodiment of this application; Figure 3 The chromatographic measurement results of the desorbed gas obtained by the cold trap in one embodiment of this application without segmentation in the gas inlet direction are as follows. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0019] Unless otherwise specified, all embodiments and optional embodiments of this disclosure can be combined to form new technical solutions.

[0020] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions.

[0021] Unless otherwise specified, all steps of this disclosure may be performed sequentially or randomly, preferably sequentially. For example, if a method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if it is mentioned that the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0022] In this application, the term "odor threshold" refers to the lowest concentration of a substance that a person can perceive an odor at, below which the odor is usually not detectable.

[0023] The main source of odor in vehicles is volatile organic compounds (VOCs) released from interior materials and components. As people begin to use vehicle odor as a factor in evaluating vehicle quality, tracing the source of odor and improving it is an urgent technical problem to be solved.

[0024] In view of this, this application provides a method for improving in-vehicle odor, comprising: S1: capturing a gas to be tested in the vehicle using a trapping tube to obtain a first captured gas and a second captured gas, and desorbing the first captured gas and the second captured gas using a secondary thermal desorption instrument to obtain a first desorbed gas and a second desorbed gas; S2: performing chromatographic separation, mass spectrometry detection, and odor detection on the first desorbed gas using a gas chromatograph-olfactometer / mass spectrometer, and recording the detection results; S3: performing chromatographic separation on the second desorbed gas, and separating the exhaust gas after separation. Segment collection was performed to obtain at least two sets of exhaust gas segments; the odor of each set of exhaust gas segments was compared with the odor of the gas to be tested in the vehicle, and the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle was selected. Combined with the detection results in S2, odor substances were screened from the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle. The odor substances simultaneously meet the following conditions: (1) the peak area ratio of the odor substance relative to the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle is ≥5% in the chromatograph; (2) the odor threshold of the odor substance is lower than 100 μg / m 3 (3) Odor substances are identified by an olfactory detector; S4: The odor substances are mixed to obtain a mixed gas, the odor of the mixed gas is verified, the odor of the mixed gas is improved by adjusting the proportion of odor substances contained in the mixed gas, and the odor of the vehicle interior is improved based on the adjusted results. By adopting the method of this application, the main sources of odor substances in the vehicle interior can be screened more efficiently, and the odor of the vehicle interior can be improved by adjusting the proportion of odor substances.

[0025] In this application, the process begins with S1: the gas to be tested inside the vehicle is captured using a capture tube to obtain a first captured gas and a second captured gas. A secondary thermal desorption instrument is then used to desorb the first captured gas and the second captured gas to obtain a first desorbed gas and a second desorbed gas.

[0026] In this application, there are no particular restrictions on the trapping tube used; for example, the trapping tube can be a Tenax trapping tube. Furthermore, it should be noted that the first and second trapping gases are obtained in the same in-vehicle environment, and therefore can be considered to have the same composition; the desorption processes performed on the first and second trapping gases are also the same, so the first and second desorbed gases can be considered to have the same composition.

[0027] In some embodiments, the collection tube can be sequentially divided into a low-boiling-point substance collection section, a medium-boiling-point substance collection section, and a high-boiling-point substance collection section in the gas inlet direction. Each of these sections includes a first packing material, a second packing material, and a third packing material, respectively. The secondary thermal desorption instrument includes a cold trap, which is sequentially divided into a low-boiling-point substance enrichment section, a medium-boiling-point substance enrichment section, and a high-boiling-point substance enrichment section in the gas inlet direction. The packing materials in these sections are the same as those in the low-boiling-point substance collection section, the medium-boiling-point substance collection section, and the high-boiling-point substance enrichment section, respectively. By dividing the collection tube into three sections, each collecting substances with different boiling points, the adsorption range of the gas to be tested inside the vehicle is improved, thereby enabling a more accurate reconstruction of the composition of the gas and facilitating subsequent screening of odor substances.

[0028] Furthermore, by setting up low-boiling-point enrichment sections, medium-boiling-point enrichment sections, and high-boiling-point enrichment sections in the cold trap of the secondary thermal desorption instrument, and ensuring that the packing materials in these sections are the same as those in the low-boiling-point, medium-boiling-point, and high-boiling-point trapping sections, respectively, it is beneficial to reduce the loss of volatile components during enrichment in the cold trap. In other words, it helps to ensure that the volatile components captured in the trapping tube are as consistent as possible with the volatile components in the final desorbed gas, thereby enabling a more accurate reconstruction of the composition of the gas to be tested inside the vehicle and facilitating subsequent screening of odor substances.

[0029] In some embodiments, the first filler may include at least one of Carbopack X, Carbograph 5TD, Carboxen1000, and Tenax TA with a particle size of 60 to 80 mesh.

[0030] In some embodiments, the second filler may include at least one of Carbopack B and TenaxTA with a particle size of 35 to 60 mesh.

[0031] In some implementations, the third filler may include at least one of Tenax GR and Carbopack C.

[0032] In some embodiments, the refrigeration temperature corresponding to the low-boiling-point substance enrichment section can be between -30°C and -20°C. Setting the refrigeration temperature corresponding to the low-boiling-point substance enrichment section within this range is beneficial for improving the enrichment effect of low-boiling-point substances. For example, the refrigeration temperature corresponding to the low-boiling-point substance enrichment section can be -30°C, -28°C, -26°C, -24°C, -22°C, -20°C, or a value within a range consisting of any two of these values.

[0033] In some embodiments, the refrigeration temperature corresponding to the enrichment section for medium-boiling-point substances can be from -20°C to 0°C. Setting the refrigeration temperature for the enrichment section within this range is beneficial for improving the enrichment effect of medium-boiling-point substances while also considering process energy consumption. For example, the refrigeration temperature corresponding to the enrichment section for low-boiling-point substances can be -20°C, -18°C, -16°C, -14°C, -12°C, -10°C, -8°C, -6°C, -4°C, -2°C, 0°C, or a value within a range of any two of these values.

[0034] In some embodiments, the refrigeration temperature corresponding to the high-boiling-point substance enrichment section can be from 0°C to 15°C. Setting the refrigeration temperature for the high-boiling-point substance enrichment section within this range is beneficial for improving the enrichment effect of high-boiling-point substances while also considering process energy consumption. For example, the refrigeration temperature corresponding to the high-boiling-point substance enrichment section can be 0°C, 2°C, 4°C, 6°C, 8°C, 10°C, 12°C, 14°C, 15°C, or a value within a range of any two of these values.

[0035] Next, in S2: the first desorbed gas is separated chromatographically, detected by mass spectrometry, and detected by odor using a gas chromatograph-odor analyzer / mass spectrometer, and the results are recorded. The first desorbed gas first enters the gas chromatograph for separation. The separated components are then split into two parallel streams. One stream enters the mass spectrometer for qualitative and quantitative analysis, and the other stream enters the odor analyzer for real-time manual odor identification. During this process, the corresponding measurement results are recorded.

[0036] Next, S3 is performed: the second desorbed gas is separated by chromatography, and the separated tail gas is collected in segments to obtain at least two sets of tail gas segments; the odor of each set of tail gas segments is compared with the odor of the gas to be tested in the vehicle, and the tail gas segment with the highest odor matching degree with the gas to be tested in the vehicle is selected. Combined with the detection results in S2, odor substances are screened from the tail gas segment with the highest odor matching degree with the gas to be tested in the vehicle. The odor substances simultaneously meet the following conditions: (1) the peak area ratio of the odor substance relative to the tail gas segment with the highest odor matching degree with the gas to be tested in the vehicle is ≥5% in the chromatograph; (2) the odor threshold of the odor substance is lower than 100 μg / m 3 (3) Odor substances are identified by the olfactory detector, where (1) and (3) can be obtained based on the detection results in S2, and the odor threshold of the odor substances in (2) can be obtained, for example, by consulting the "Compilation of Compound Odor Thresholds" (Second Edition).

[0037] The composition of the gases tested inside a vehicle is complex, and different interactions may exist between the components (such as synergistic and antagonistic effects). These interactions ultimately form the odor that can be perceived by humans. Therefore, when analyzing the odor inside a vehicle, the contribution of a single component cannot be considered alone. By collecting exhaust gas in segments and comparing the odor of each segment with the odor of the gases tested inside the vehicle, the exhaust gas segment with the highest odor matching degree is selected. Then, the components of this exhaust gas segment are analyzed in detail. This approach preserves the possible different interactions between the components in the exhaust gas segment, thus more accurately reproducing the odor inside the vehicle, while also improving analytical efficiency.

[0038] In this application, after obtaining the exhaust gas segment with the highest odor matching degree with the test gas inside the vehicle, odor substances are screened from the exhaust gas segment based on the detection results of S2 and known literature. The odor substances simultaneously meet the following conditions: (1) the peak area ratio of the odor substance relative to the exhaust gas segment with the highest odor matching degree with the test gas inside the vehicle is ≥5% in the chromatograph; (2) the odor threshold of the odor substance is lower than 100 μg / m³. 3 (3) Odor substances are identified by the olfactory detector. The above screening conditions are beneficial for obtaining the components that contribute more to the odor in this exhaust section.

[0039] In some embodiments, at least two exhaust gas segments include two to five exhaust gas segments. By controlling the number of separated exhaust gas segments within the above range, the analytical efficiency can be further improved, while keeping the number of components in each exhaust gas segment within an appropriate range, thereby taking into account the contribution of the interactions between components (e.g., synergistic effects, antagonistic effects, etc.) to the final odor.

[0040] In some implementations, segmented collection of the separated exhaust gas includes collecting the separated exhaust gas in equal time segments. Collecting within equal time segments helps establish standardized operations and facilitates the implementation of large-scale industrial testing.

[0041] After S3, proceed to S4: mix the odor substances to obtain a mixed gas, verify the odor of the mixed gas, improve the odor of the mixed gas by adjusting the proportion of odor substances contained in the mixed gas, and improve the odor inside the vehicle based on the adjusted results.

[0042] After identifying odor substances in S3, these substances are mixed. For example, they can be mixed according to their relative content in the test gas inside the vehicle to obtain a mixed gas. Odor verification of this mixed gas serves two purposes: firstly, to verify that it accurately reproduces the odor inside the vehicle; and secondly, to prepare for subsequent odor improvement. As mentioned above, since odor substances may have different interactions (e.g., synergistic effects, antagonistic effects, etc.), adjusting the proportion of odor substances in the mixed gas can improve its odor. The adjusted result can provide direction for improving the odor inside the vehicle, ultimately achieving odor improvement.

[0043] In some embodiments, improving the odor of the gas mixture may include improving odor intensity and flavor profile. In some embodiments, improving the odor of the gas mixture may include improving odor intensity.

[0044] Example The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0045] Methods to improve car interior odor (1) Referring to HJ / T 400-2007, Tenax trapping tubes are used to trap the gas to be tested in the vehicle, resulting in a first trapped gas and a second trapped gas. The trapping tube is divided into a low-boiling-point substance trapping section, a medium-boiling-point substance trapping section, and a high-boiling-point substance trapping section in the gas inlet direction, and all three sections are isolated with inert quartz wool. The low-boiling-point substance trapping section contains Tenax TA with a particle size of 60 to 80 mesh, the medium-boiling-point substance trapping section contains Tenax TA with a particle size of 35 to 60 mesh, and the high-boiling-point substance trapping section contains Tenax GR.

[0046] (2) The first and second captured gases are desorbed using a secondary thermal desorber to obtain the first and second desorbed gases. The secondary thermal desorber includes a cold trap, which is divided into a low-boiling-point enrichment section, a medium-boiling-point enrichment section, and a high-boiling-point enrichment section in the gas inlet direction. The packing materials in the low-boiling-point enrichment section, the medium-boiling-point enrichment section, and the high-boiling-point enrichment section are the same as those in the low-boiling-point capture section, the medium-boiling-point capture section, and the high-boiling-point capture section. The refrigeration temperature corresponding to the low-boiling-point enrichment section is -25℃, the refrigeration temperature corresponding to the medium-boiling-point enrichment section is -5℃, and the refrigeration temperature corresponding to the high-boiling-point enrichment section is 5℃.

[0047] (3) The first desorbed gas was separated by chromatography, detected by mass spectrometry, and detected by odor using a gas chromatograph-odor analyzer / mass spectrometer. The components separated by the gas chromatograph were split into two parallel streams. One stream was sent to the mass spectrometer for qualitative and quantitative analysis, and the other stream was sent to the odor analyzer for real-time manual odor identification. The corresponding measurement results were recorded during this period. The chromatographic analysis conditions were as follows: DB-1ms non-polar chromatographic column (30m×0.25mm×0.25μm), carrier gas was 99.999% high-purity helium, carrier gas flow rate was 1.0mL / min; injection port temperature was 200℃; chromatographic temperature program: initial temperature 40℃, constant temperature for 5min, temperature increased to 280℃ at a rate of 5℃ / min, constant temperature for 10min, and total chromatographic separation time was 30min. Figure 2 The chromatographic measurement results of the first desorbed gas are shown. As a control, steps (1) to (3) were repeated, except that the cold trap was not segmented in the gas inlet direction and only contained Tenax TA packing material with a particle size of 35 to 60 mesh, thus obtaining... Figure 3 The measurement results. By comparison Figure 2 and Figure 3 It can be seen that by setting the cold trap in segments, with each segment containing the same packing material as the corresponding segment of the trapping tube, more volatile components are enriched and eventually enter the chromatograph, thus enabling a more accurate reconstruction of the composition of the gas to be tested in the vehicle, which is more conducive to the subsequent screening of odor substances.

[0048] (4) The second desorbed gas is separated by chromatography under the same conditions as in step (3), and the separated tail gas is collected in segments at equal time intervals to obtain five tail gas segments.

[0049] (5) Five evaluators compared the odors of the five exhaust gas sections collected with the odors of the gas to be tested inside the vehicle, and scored them according to the scoring criteria in Table 1 below. The final statistical results of the exhaust gas section scores are shown in Table 2 below: Table 1 Odor Similarity Scoring Table

[0050] Table 2 Evaluation of Odor Similarity of Exhaust Gas Sections for Each Group

[0051] As shown in Table 2, the exhaust gas from the second group has the highest similarity to the smell inside the vehicle.

[0052] (6) Retrieve chromatographic data, mass spectrometry data, and odor records of the tail gas segment (i.e., the second tail gas segment) collected over 6–12 minutes, and select the following screening criteria: the peak area ratio of odor substances relative to the second tail gas segment (hereinafter referred to as relative peak area ratio) ≥ 5% in the chromatograph, and the odor threshold < 100 μg / m³. 3 The odor substances were identified using an olfactory detector, ultimately pinpointing four odor substances as follows: 1. Hexanal: relative peak area percentage 18.2%, odor threshold 3 μg / m³ 3 Odor characteristics: grassy smell; 2. Triethylamine: relative peak area percentage 12.5%, odor threshold 24 μg / m³ 3 Odor characteristics: strong fishy smell, ammonia smell; 3. Toluene: relative peak area percentage 9.8%, odor threshold 10 μg / m³ 3 Odor characteristics: Slightly aromatic and pungent odor; 4. Pentanal: relative peak area percentage 7.6%, odor threshold 62 μg / m³ 3 Odor characteristics: pungent odor, leather smell.

[0053] (7) A mixed gas was prepared according to the relative contents of the above four substances in the exhaust section (hexanal:triethylamine:toluene:pentanal = 18.2%:12.5%:9.8%:7.6%), and the odor of the mixed gas was verified by five evaluators scoring it according to the scoring criteria in Table 1. The average score was 8.5 points, which was highly consistent with the similarity of the gas to be tested in the vehicle, confirming that the four substances were the main sources of odor.

[0054] (8) By adjusting the relative content of the above four odor substances in the mixed gas through gradient, five different mixed gas mixtures were prepared. The evaluators scored the odor intensity according to the scoring criteria in Table 3 below, and selected the better combination. The test results are as follows: Table 3 Odor Intensity Scoring Table

[0055] 1. Original ratio: Odor intensity level 3.0 (obvious odor, slight irritation); 2. Optimized formula 1: Hexanal reduced by 40%, other components reduced by 20%, odor rating 2.7; 3. Optimized formula 2: hexanal reduced by 45%, triethylamine reduced by 30%, toluene and pentanal reduced by 25%, odor rating 2.5 (obvious odor, non-irritating); 4. Optimized ratio 3: The overall proportion is significantly reduced (hexanal is reduced by 60%, and the other components are reduced by 70%), and the odor level is 2.0 (the odor can be detected, but it is not irritating).

[0056] (9) Taking into account cost and process considerations, based on the optimized ratio 2, the process of the three major components of the vehicle seats, plastic trim panels and adhesives was modified: the baking time of the components was controlled and the raw material formula was optimized. Finally, the optimized vehicle interior gas was retested. After retesting, the relative content of the above four odor substances was consistent with the relative content in the optimized ratio 2. The odor level of the whole vehicle interior was stabilized at level 2.5, which achieved the improvement of vehicle interior odor.

[0057] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. A method for improving the odor inside a vehicle, characterized in that, include: S1: The gas to be tested inside the vehicle is captured using a capture tube to obtain a first captured gas and a second captured gas. The first captured gas and the second captured gas are desorbed using a secondary thermal desorption instrument to obtain a first desorbed gas and a second desorbed gas. S2: Use a gas chromatograph-olfactometer / mass spectrometer to perform chromatographic separation, mass spectrometry detection and olfacto detection on the first desorbed gas, and record the detection results; S3: Perform chromatographic separation on the second desorbed gas, and collect the separated exhaust gas in segments to obtain at least two sets of exhaust gas segments; compare the odor of each set of exhaust gas segments with the odor of the gas to be tested inside the vehicle, select the exhaust gas segment with the highest odor matching degree with the gas to be tested inside the vehicle, and combine the detection results in S2 to screen out odor substances from the exhaust gas segment with the highest odor matching degree with the gas to be tested inside the vehicle. The odor substances simultaneously meet the following conditions: (1) In the chromatograph, the peak area of ​​the odor substance relative to the exhaust gas segment with the highest odor matching degree with the gas to be tested in the vehicle accounts for ≥5%; (2) The odor threshold of the odorant is less than 100 μg / m³. 3 ; (3) The odorous substance was identified by an olfactory detector; S4: Mix the odor substances to obtain a mixed gas, verify the odor of the mixed gas, improve the odor of the mixed gas by adjusting the proportion of odor substances contained in the mixed gas, and improve the odor of the vehicle interior based on the adjusted results.

2. The improved method according to claim 1, characterized in that: The trapping tube is divided into a low-boiling-point substance trapping section, a medium-boiling-point substance trapping section, and a high-boiling-point substance trapping section in the gas inlet direction. The low-boiling-point substance trapping section, the medium-boiling-point substance trapping section, and the high-boiling-point substance trapping section respectively include a first packing, a second packing, and a third packing. The secondary thermal desorption apparatus includes a cold trap, which is divided into a low-boiling-point substance enrichment section, a medium-boiling-point substance enrichment section, and a high-boiling-point substance enrichment section in sequence along the gas inlet direction. The packing materials in the low-boiling-point substance enrichment section, the medium-boiling-point substance enrichment section, and the high-boiling-point substance enrichment section are the same as those in the low-boiling-point substance trapping section, the medium-boiling-point substance trapping section, and the high-boiling-point substance trapping section, respectively.

3. The improved method according to claim 1, characterized in that: S3 satisfies at least one of the following: (1) The at least two sets of exhaust gas sections include two to five sets of exhaust gas sections; (2) The segmented collection of the separated exhaust gas includes collecting the separated exhaust gas in segments at equal time intervals.

4. The improved method according to claim 1, characterized in that: Improving the odor of the mixed gas includes improving odor intensity and flavor profile; optionally, improving the odor of the mixed gas includes improving odor intensity.

5. The improved method according to claim 2, characterized in that, The first filler includes at least one of Carbopack X, Carbograph 5TD, Carboxen 1000, and Tenax TA with a particle size of 60 to 80 mesh.

6. The improvement method according to claim 2, characterized in that, The second filler includes at least one of Carbopack B and Tenax TA with a particle size of 35 to 60 mesh.

7. The improved method according to claim 2, characterized in that, The third packing material includes at least one of Tenax GR and Carbopack C.

8. The improved method according to claim 2, characterized in that, The refrigeration temperature corresponding to the low-boiling-point substance enrichment section is -30℃ to -20℃.

9. The improvement method according to claim 2, characterized in that, The refrigeration temperature corresponding to the enrichment section of the medium-boiling-point substance is -20℃ to 0℃.

10. The improved method according to claim 2, characterized in that, The refrigeration temperature corresponding to the high-boiling-point substance enrichment section is 0℃ to 15℃.

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