A portable rapid car health detection device using olfactory chips

Abstract

The invention discloses a portable automobile health rapid detection device using an olfactory chip, and relates to the technical field of automobile gas detection. The invention divides the interior of an automobile into multiple areas, efficiently monitors the air quality inside the automobile, and efficiently monitors the concentration distribution of harmful gases inside the automobile by optimizing the position and number of sensors, combining an air flow model and an air quality model, and timely discovers and handles air quality problems; wherein, optimizing the sensor layout can cover the interior space of the automobile to the greatest extent, accurately monitor the air quality, and improve the monitoring coverage and measurement accuracy; through real-time monitoring and data processing by sensors, real-time monitoring and timely feedback of the air quality inside the automobile can be achieved, helping car owners and passengers to take measures to improve the air quality in a timely manner; a mechanism for increasing the number of sensors is introduced, and the sensor layout is dynamically adjusted according to actual conditions, so as to improve adaptability and flexibility and make the monitoring system more intelligent and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile gas detection, and in particular to a portable automobile health rapid detection device utilizing an olfactory chip. Background Art

[0002] With the increasing popularity and usage of cars, people are paying more and more attention to the air quality inside cars. There may be various harmful gases inside cars, such as VOCs (volatile organic compounds) such as formaldehyde and benzene, carbon dioxide, carbon monoxide, etc. These harmful gases pose a threat to human health. Therefore, it is very important to monitor and detect the air quality inside cars.

[0003] Traditional methods for monitoring the air quality inside cars often rely on handheld detection equipment or fixed monitoring equipment, which have the disadvantages of complex operation, limited monitoring range, and low monitoring efficiency. In order to solve these problems, some methods for monitoring the air quality inside cars based on sensor networks have emerged in recent years. By arranging multiple sensors inside the car and using sensor network technology for data collection and processing, real-time monitoring and analysis of the air quality inside the car can be achieved.

[0004] However, the existing sensor network-based vehicle interior air quality monitoring methods still have some problems, such as low monitoring coverage due to unreasonable sensor layout and high cost due to too many sensors.

[0005] To this end, a new automobile health detection method is proposed, which can efficiently monitor the interior air quality of the car, optimize the sensor layout, improve the monitoring efficiency and accuracy, and reduce the monitoring cost, so as to better protect the health and safety of the passengers. Summary of the invention

[0006] The purpose of the present invention is to solve the problem of unreasonable sensor layout of automobile gas detection equipment in the prior art, and to propose a portable automobile health rapid detection device using an olfactory chip.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A portable rapid vehicle health detection device using an olfactory chip, comprising a pump, an olfactory chip, a processor, a display screen, an audible and visual alarm, a power supply, and a sensor module;

[0009] The olfactory chip controls multiple airflow sensors installed inside the car, combines the air flow model and the air quality model to build a sensor response model, describes the changes in VOCs concentration inside the vehicle, and introduces an optimization algorithm to improve it. The steps are as follows:

[0010] S1 initializes the particle group N and sensor position N: each particle N k Represents a layout scheme of the sensor network, where the sensor location is represented by the three-dimensional coordinate N k (x, y, z) represents; initialization particle speed V k0 and position N k，0 (x0, y0, z0), and record the historical best position N of each particle k，history (x history ,y history , z history ) and the global optimal position N k，max (x max ,y max , z max );

[0011] S2 updates the speed and position of each particle according to its current position and speed as well as the historical best position and the global best position;

[0012] S3: For each particle, if its current position is better than its historical best position, then update its historical best position; if the current position of any particle is better than the global best position, then update the global best position;

[0013] S4 repeats S2 and S3 until the stop condition is met.

[0014] Preferably, the three-dimensional area of ​​the interior space of the automobile is divided into multiple areas in the air flow model, including a cockpit area Ω1, an air-conditioning outlet area Ω2, a door area Ω3, a luggage compartment area Ω4 and an engine compartment area Ω5.

[0015] Preferably, the step of updating its speed and position includes:

[0016] ①Update speed:

[0017] V i (t+1)=ωV i (t)+c1r 1i (Pbest i -X i (t))+c2r 2i (Gbest i -X i (t))

[0018] Among them, V i (t+1) is particle N k The velocity at time step t+1, ω is the inertia weight, c1 and c2 are acceleration factors, r 1i and r 2i is a random number in [0, 1];

[0019] ②Update location:

[0020] X i (t+1)=X i (t)+V i (t+1)

[0021] Preferably, in step S3, for each region Ω i [i=1,2,3,4,5], if the concentration of a region exceeds the threshold, increase the number of sensors, and set the concentration of the i-th region to C i , the threshold is T i , the threshold gradient is G i , the number of new sensors N i for:

[0022]

[0023] in, Indicates rounding up *.

[0024] Preferably, the Navier-Stokes equations for the five-region flow are expressed as:

[0025]

[0026] Among them, i is the region index (i=1, 2, 3, 4, 5), representing different regions of Ω, ρ is the air density, u is the velocity vector, p is the pressure, μ is the dynamic viscosity, and f is the external force.

[0027] Preferably, the boundary conditions include a no-slip condition of a solid boundary and a velocity or pressure condition of a fluid boundary, and the no-slip condition of a solid boundary is expressed as:

[0028] u|Γ=0

[0029] The velocity or pressure condition of the fluid boundary of the air inside the car is set according to the regional conditions;

[0030] I. The cockpit area is regarded as a solid wall, so its boundary condition is set to a no-slip condition, expressed as:

[0031]

[0032] Among them, u1 is the velocity field, p1 is the pressure field, ρ1 is the air density, μ1 is the dynamic viscosity coefficient, and f1 is the external force, including gravity and volume force caused by passenger activities;

[0033] II Air conditioning outlet. The air flow near the air conditioning outlet is a relatively uniform inflow flow, which is regarded as an inlet boundary condition. The inlet velocity is determined according to the setting of the air conditioning system, that is, the air velocity in this area is equal to the velocity of the external environment, which is expressed as:

[0034]

[0035] Among them, u inlet is the velocity vector at the inlet, is the unit normal vector pointing to the entrance, and u2 is the velocity magnitude at the entrance;

[0036] III. Door area: the door area is set as an open boundary to simulate the open state of the door and allow the air to flow freely, or it is set as a boundary connected to the external environment to determine the air flow according to the air pressure and temperature of the external environment;

[0037]

[0038] Where u3 is the air velocity in the door area, p3 is the air pressure in the door area, μ3 is the dynamic viscosity of the air, ρ3 is the density of the air, g is the acceleration due to gravity, and f3 is the volume force in the door area, including the airflow from the opening and closing of the window;

[0039] IV luggage compartment area, the luggage compartment area is set to be a solid wall surface similar to the bottom of the cabin area, the velocity is zero, and the pressure is determined according to the external environment and the pressure of the gas inside the luggage compartment;

[0040] Solid wall conditions:

[0041]

[0042] in, is the normal vector of the trunk area exit;

[0043] V Engine compartment area. The engine compartment area is usually located at the front of the vehicle. The boundary conditions need to take into account the impact of engine exhaust gas on air flow. The engine exhaust gas generates a velocity field u on the air flow. exhaust , the exhaust gas velocity field is a Gaussian model;

[0044]

[0045] Among them, U exhaust is the velocity of the exhaust gas, (x0, y0, z0,) is the location of the exhaust port, σ is the standard deviation of the Gaussian function, is a unit vector, used to indicate the direction of velocity;

[0046] Using the above-mentioned Gaussian model, the flow of exhaust gas in the engine compartment area is obtained, and then the volume force generated by the exhaust gas is calculated to describe the driving effect of the exhaust gas on the surrounding air;

[0047]

[0048] Calculate the volume force generated by the exhaust gas on the air flow, and obtain the driving effect of the exhaust gas on the air flow by calculating the gradient of the exhaust gas velocity field;

[0049] The momentum equation is used in combination with boundary conditions and initial conditions for calculation, and the following boundary conditions are considered;

[0050] Solid wall condition: the solid parts in the engine compartment (such as the engine, body, etc.) are regarded as solid walls with a velocity of zero, that is, the velocity on the solid surface in the engine compartment is zero:

[0051] u engine =0

[0052] The inlet boundary condition uses the velocity field of the exhaust gas as the inlet boundary condition to describe the effect of the exhaust gas on the air flow:

[0053] u inlet =u exhaust

[0054] The outlet boundary condition describes the air outflow with the pressure or velocity field at the outlet. The pressure at the outlet generally does not change along the normal direction, that is, the pressure is uniform in this direction. The pressure gradient at the outlet is zero, so:

[0055]

[0056] in, is the normal vector of the outlet boundary. The zero pressure gradient ensures that there is no flow driven by the pressure gradient at the outlet, that is, the fluid will not accelerate or decelerate in this direction;

[0057] The initial velocity field and initial pressure field are set according to the vehicle motion state or experimental data;

[0058]

[0059] The momentum equation is:

[0060]

[0061] Among them, the left side is the inertia term and convection term of the air, and the right side is the pressure gradient term, viscosity term, external volume force term and exhaust gas volume force term. Combined with the boundary conditions and initial conditions, the impact of the engine exhaust gas on the air flow and the specific conditions of the air flow are calculated.

[0062] Preferably, in the air quality model, for the luggage compartment area, the diffusion coefficient is greater than that of the other three areas except the air-conditioning outlet area, and the convection velocity is less than that of the other three areas except the air-conditioning outlet area, and the source term is zero; for the air-conditioning outlet area, the diffusion coefficient is greater than that of other areas, and the convection velocity is less than that of other areas.

[0063] Compared with the prior art, the present invention has the following advantages:

[0064] The present invention divides the interior of a car into multiple areas, efficiently monitors the air quality inside the car, and by optimizing the position and number of sensors and combining air flow models and air quality models, efficiently monitors the concentration distribution of harmful gases inside the car, and promptly discovers and handles air quality problems. Among them, optimizing the sensor layout can cover the interior space of the car to the greatest extent, accurately monitor the air quality, and improve the monitoring coverage and measurement accuracy. Through real-time monitoring and data processing by sensors, real-time monitoring and timely feedback of the air quality inside the car can be achieved, helping car owners and passengers to take timely measures to improve the air quality. A mechanism for increasing the number of sensors is introduced, and the sensor layout is dynamically adjusted according to actual conditions, thereby improving adaptability and flexibility and making the monitoring system more intelligent and reliable.

[0065] By timely monitoring and effectively controlling the air quality inside the car, the accumulation and emission of harmful gases can be reduced, the risk of air pollution can be reduced, and the health and comfort of passengers can be guaranteed. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0067] A portable automobile health rapid detection device using an olfactory chip includes a pump, an olfactory chip, a processor, a display screen, an audible and visual alarm, a power supply and a sensor module. The device collects the gas to be tested by pumping, reacts with the metal oxide gas-sensitive material of the chip to produce an electrical signal change, and feeds back the detection result to the front end after certain processing, and displays the gas concentration value in real time. When the concentration of the measured gas reaches the alarm threshold, the audible and visual alarm is activated to remind the user to stay away from or deal with the odor in the car in time.

[0068] Relying on the olfactory chip, the sensor module includes multiple airflow sensors set inside the car. The olfactory chip and the airflow sensor are connected by communication. X represents the collection of sensors. The sensor response is proportional to the concentration of odor and VOCs in the air, but is also affected by the characteristics of the sensor itself. In order to optimize the position and number of sensors to improve coverage and measurement effect, the sensor response model is established by combining the air flow model and the air quality model, that is, to determine the position and number of sensors in each area to achieve the best detection effect, that is, to be able to more clearly describe the changes in VOCs concentration inside the vehicle. The optimization algorithm is introduced to improve it. The steps are as follows:

[0069] S1 initializes the particle group N and sensor position N: each particle N k Represents a layout scheme of the sensor network, where the sensor location is represented by the three-dimensional coordinate N k (x, y, z) represents; initialization particle speed V k0 and position N k，0 (x0, y0, z0), and record the historical best position N of each particle k，history (x history ,y history , z history ) and the global optimal position N k，max (x max ,y max , z max );

[0070] S2 updates the speed and position of each particle according to its current position and speed as well as the historical best position and the global best position;

[0071] ①Update speed:

[0072] V i (t+1)=ωV i (t)+c1r 1i (Pbest i -X i (t))+c2r 2i (Gbest i -X i (t))

[0073] Among them, V i (t+1) is particle N k The velocity at time step t+1, ω is the inertia weight, c1 and c2 are acceleration factors, r 1i and r 2i is a random number in [0, 1];

[0074] ②Update location:

[0075] Xi (t+1)=X i (t)+V i (t+1)

[0076] S21 For each region Ω i [i=1,2,3,4,5], if the concentration of a region exceeds the threshold, increase the number of sensors, and set the concentration of the i-th region to C i , the threshold is T i , the threshold gradient is G i , the number of new sensors N i for:

[0077]

[0078] in, Indicates rounding up *;

[0079] S3 updates the historical best position of each particle if its current position is better than its historical best position; if the current position of any particle is better than the global best position, the global best position is updated.

[0080] S4 repeats S2 and S3 until the stopping condition is met. Generally, a maximum number of iterations is set.

[0081] In response to the above, in order to obtain the harmful gas concentration data inside the car, the position and number of sensors are optimized to improve the coverage and measurement effect, and the sensor response model is established by combining the air flow model and the air quality model.

[0082] Through mathematical models and optimization algorithms, we can achieve rapid monitoring of the air quality inside the car and optimize the sensor layout. Combined with the air flow model and air quality model, we can accurately calculate the concentration distribution of VOCs in the air and improve monitoring accuracy. Through real-time monitoring and data processing by sensors, we can achieve real-time monitoring and feedback of the air quality inside the car. We introduce a mechanism to increase the number of sensors, dynamically adjust the sensor layout according to actual conditions, and improve adaptability and flexibility.

[0083] The specific steps are as follows:

[0084] 1. Establish an air flow model;

[0085] The interior space of the car is a three-dimensional region Ω, whose boundary is Γ. The space Ω is expressed as:

[0086] Ω=(x,y,z)|0≤x≤A, 0≤y≤B, 0≤z≤C

[0087] Considering the characteristics of air flow, possible pollution sources, the detection range and sensitivity of sensors, different areas have different detection importance, and Ω is divided into five major areas:

[0088] Cabin area Ω1: The cabin area is the main area inside the car, usually including seats, carpets, steering wheels, etc. This area is most likely to be affected by odors and VOCs released by passengers and interior materials. s impact.

[0089] Air conditioning outlet area Ω2: The air conditioning system will draw in outside air and exhaust it into the vehicle, affecting the air quality. It is used to monitor the impact of the air conditioning system on air quality.

[0090] Door area Ω3: There are poor sealing problems and pollution sources around the doors, such as the inside of the doors and near the windows.

[0091] Trunk area Ω4: The trunk of a car stores a variety of items, some of which release odors or VOCs.

[0092] Engine compartment area Ω5: There is a smell of combustion products and engine oil in the engine compartment.

[0093] The Navier-Stokes equations for the five-region flow are expressed as:

[0094]

[0095] Where i is the region index (i=1, 2, 3, 4, 5), representing different regions of Ω, ρ is the air density, u is the velocity vector, p is the pressure, μ is the dynamic viscosity, and f is the external force;

[0096] The boundary conditions include the no-slip condition of the solid boundary and the velocity or pressure condition of the fluid boundary. The no-slip condition of the solid boundary is expressed as:

[0097] u|Γ=0

[0098] The velocity or pressure condition of the fluid boundary of the air inside the car is set according to the regional conditions;

[0099] 1. The cockpit area is regarded as a solid wall, so its boundary condition is set as a no-slip condition, expressed as:

[0100]

[0101] Among them, u1 is the velocity field, p1 is the pressure field, ρ1 is the air density, μ1 is the dynamic viscosity coefficient, and f1 is the external force, including gravity and volume force caused by passenger activities;

[0102] 2. Air conditioning outlet: The air flow near the air conditioning outlet is a relatively uniform inflow flow, which is regarded as an inlet boundary condition. The inlet velocity is determined according to the setting of the air conditioning system, that is, the air velocity in this area is equal to the velocity of the external environment, which is expressed as:

[0103]

[0104] Among them, u inlet is the velocity vector at the inlet, is the unit normal vector pointing to the entrance, and u2 is the velocity magnitude at the entrance;

[0105] 3. Door area: The door area is set as an open boundary to simulate the open state of the door, allowing air to flow freely, or set as a boundary connected to the external environment to determine the air flow according to the air pressure and temperature of the external environment;

[0106]

[0107] Among them, u3 is the air velocity in the door area, p3 is the air pressure in the door area, μ3 is the dynamic viscosity of the air, ρ3 is the density of the air, g is the acceleration due to gravity, and f3 is the volume force in the door area, including the airflow from the opening and closing of the windows.

[0108] 4. The luggage compartment area is set as a solid wall similar to the bottom of the cabin area, with a velocity of zero and a pressure determined according to the external environment and the pressure of the gas inside the luggage compartment.

[0109] Solid wall conditions:

[0110]

[0111] in, is the normal vector of the trunk area exit;

[0112] 5. Engine compartment area. The engine compartment area is usually located at the front of the vehicle. The boundary conditions need to take into account the impact of engine exhaust gas on air flow. The engine exhaust gas generates a velocity field u on the air flow. exhaust , the exhaust gas velocity field is a Gaussian model;

[0113]

[0114] Among them, U exhaust is the velocity of the exhaust gas, (x0, y0, z0) is the location of the exhaust port, σ is the standard deviation of the Gaussian function, is a unit vector, used to indicate the direction of velocity;

[0115] Using the above-mentioned Gaussian model, the flow of exhaust gas in the engine compartment area is obtained, and then the volume force generated by the exhaust gas is calculated to describe the driving effect of the exhaust gas on the surrounding air;

[0116]

[0117] Calculate the volume force generated by the exhaust gas on the air flow, and obtain the driving effect of the exhaust gas on the air flow by calculating the gradient of the exhaust gas velocity field;

[0118] The momentum equation is used in combination with boundary conditions and initial conditions for calculation, and the following boundary conditions are considered;

[0119] Solid wall condition: the solid parts in the engine compartment (such as the engine, body, etc.) are regarded as solid walls with a velocity of zero, that is, the velocity on the solid surface in the engine compartment is zero:

[0120] u engine =0

[0121] The inlet boundary condition uses the velocity field of the exhaust gas as the inlet boundary condition to describe the effect of the exhaust gas on the air flow:

[0122] u inlet =u exhaust

[0123] The outlet boundary condition describes the air outflow with the pressure or velocity field at the outlet. The pressure at the outlet generally does not change along the normal direction, that is, the pressure is uniform in this direction. The pressure gradient at the outlet is zero, so:

[0124]

[0125] in, is the normal vector of the outlet boundary. The zero pressure gradient ensures that there is no flow driven by the pressure gradient at the outlet, that is, the fluid will not accelerate or decelerate in this direction;

[0126] The initial velocity field and initial pressure field are set according to the vehicle motion state or experimental data.

[0127]

[0128] The momentum equation is:

[0129]

[0130] Among them, the left side is the inertia term and convection term of the air, and the right side is the pressure gradient term, viscosity term, external volume force term and exhaust gas volume force term. Combined with the boundary conditions and initial conditions, the impact of the engine exhaust gas on the air flow and the specific conditions of the air flow are calculated.

[0131] 2. Build an air quality model

[0132] Air quality is affected by diffusion and convection, and satisfies the diffusion equation and continuity equation in time and space. The air quality model is established with the diffusion-continuity equation:

[0133]

[0134] Where D is the diffusion coefficient. For the luggage compartment area, the diffusion coefficient is small, the convection velocity is small, and the source term is zero. For the air-conditioning outlet area, the diffusion coefficient is large, the convection velocity is large, and the source term is zero or the emission rate related to the air-conditioning system. ρ is the air density, u is the air velocity, and C is the pollutant concentration, which represents pollutants such as odors and VOCs. is the Laplace operator, t represents the observation time point;

[0135] Taking into account the effects of diffusion and convection, the overall change equation of substance concentration is obtained:

[0136]

[0137] Among them, Q VOCS represents the source term;

[0138] Use numerical methods (such as finite difference method, finite element method, etc.) to solve this equation and obtain the variation of substance concentration over time and space. Taking the finite element method as an example, the calculation is as follows:

[0139] S1 will Ω i The area within (i=1, 2, 3, 4, 5) is divided into N xi ×N yi ×N zi Small cubic units (here regarded as a cube, with side lengths of A, B, and C, divided into N xi ×N yi ×N zi The small cubic units are just for the convenience of understanding statistics, just N xi ×N yi ×N zi It is also possible to directly divide it into K equal small cubic units, just for the sake of understanding) Select a node in each unit and mark it as Ω i，a，b，c ;

[0140] S2 selects a three-dimensional linear shape function as the shape function in each element, for example, for Ω i，a，b，c Unit, shape function is τ i，a，b，c (x, y, z), where τ i，a，b，c (x, y, z) in Ω i，a，b，c The unit is a linear function;

[0141] S3 multiplies the mass conservation equation by a test function And integrating over the entire cubic region gives the weak form:

[0142]

[0143] S4 discretizes the weak form using shape functions within each cell;

[0144]

[0145] S5 assembles and solves the equation, Ω i，a，b，c The discretized equations within the unit are added together to obtain the overall algebraic system of equations;

[0146]

[0147] Among them, Ω e，i，a，b，c Represents Ω i，a，b，c The volume of the unit, dΩ i，a，b，c represents the volume of microelement;

[0148] For the fixed concentration boundary, the concentration on the boundary node is set to a fixed value C. bc For fixed flow boundaries, the mass flow rate at the boundary nodes is set to a fixed value q bc ;

[0149]

[0150] Apply boundary conditions to the algebraic system of equations to obtain the complete linear system;

[0151] Ax=b

[0152] Where A is the coefficient matrix, for the boundary conditions of applying fixed concentration and the boundary conditions of applying fixed flow:

[0153] ①: Boundary conditions of fixed concentration

[0154] Set the concentration value on the boundary node to a fixed value C bc , this value can be directly substituted into the corresponding position in the coefficient matrix A and the right-hand vector b;

[0155] ②: For the boundary condition of fixed flow, it can be achieved by modifying the left vector b in the linear system. The fixed flow at the boundary node j is q bc , then there is an additional equation corresponding to the system of equations:

[0156]

[0157] Among them, A mn are the elements of the coefficient matrix A, Cm is the concentration value at node j, b i are the elements of the right-hand side vector b;

[0158] Thus, the concentration value at each node can be obtained;

[0159] S6 concentration value post-processing, according to the solution results, calculate the average concentration C avg ;

[0160]

[0161] Where V is the volume of the entire region, Ω i is the entire Ω i area;

[0162] Through the above steps, the mass conservation equation in three dimensions is solved to obtain the variation of substance concentration inside the car with time and space.

[0163] The present invention divides the interior of a car into multiple areas, efficiently monitors the air quality inside the car, and by optimizing the position and number of sensors and combining air flow models and air quality models, efficiently monitors the concentration distribution of harmful gases inside the car, and promptly discovers and handles air quality problems. Among them, optimizing the sensor layout can cover the interior space of the car to the greatest extent, accurately monitor the air quality, and improve the monitoring coverage and measurement accuracy. Through real-time monitoring and data processing by sensors, real-time monitoring and timely feedback of the air quality inside the car can be achieved, helping car owners and passengers to take timely measures to improve the air quality. A mechanism for increasing the number of sensors is introduced, and the sensor layout is dynamically adjusted according to actual conditions, thereby improving adaptability and flexibility and making the monitoring system more intelligent and reliable.

[0164] By timely monitoring and effectively controlling the air quality inside the car, the accumulation and emission of harmful gases can be reduced, the risk of air pollution can be reduced, and the health and comfort of passengers can be guaranteed.

[0165] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A portable rapid vehicle health detection device using an olfactory chip, characterized in that: Includes pump, olfactory chip, processor, display screen, sound and light alarm, power supply and sensor module; The olfactory chip controls multiple airflow sensors installed inside the car, combines the air flow model and the air quality model to establish a sensor response model, describes the changes in VOCs concentration inside the vehicle, and introduces an optimization algorithm to improve it. The steps are as follows: S1, initialize particle group N and sensor position N: each particle Represents a layout scheme for a sensor network, where sensor locations are expressed in three-dimensional coordinates Indicates; Initialize the speed of the particle and location , and record the historical best position of each particle and the global optimal position ; S2, for each particle, update its speed and position according to its current position and speed as well as the historical best position and the global best position; ①Update speed: ； in, It is a particle At time step speed, is the inertia weight, and is the acceleration factor, and is a random number in [0,1]; ②Update location: ； And thereby complete the update of each particle's speed and position; S3, for each particle, if its current position is better than its historical best position, then update its historical best position; if the current position of any particle is better than the global best position, then update the global best position; S4, repeat S2 and S3 until the stop condition is met; The air flow model divides the three-dimensional area of ​​the car's interior space into multiple areas, including the cockpit area , Air conditioning outlet area , Door area , luggage area and engine compartment area ; In step S3, for each region , if the regional concentration exceeds the threshold, increase the number of sensors, and set the concentration of the i-th region to , the threshold is , the threshold gradient is , the number of new sensors for: ； in, Indicates that Round up; Among them, the Navier-Stokes equations for the five major regional flows are expressed as: ； Where i is the region index, i=1,2,3,4,5, representing different regions of Ω, ρ is the air density, u is the velocity vector, p is the pressure, μ is the dynamic viscosity, For external forces; The boundary conditions include the no-slip condition of the solid boundary and the velocity or pressure condition of the fluid boundary. The no-slip condition of the solid boundary is expressed as: ； The velocity or pressure condition of the fluid boundary of the air inside the car is set according to the regional conditions; Ⅰ Cabin area, the cabin area is regarded as a solid wall, so its boundary condition is set as a no-slip condition, expressed as: ； in, is the velocity field, It is a pressure field. is the air density, is the dynamic viscosity coefficient, are external forces, including gravity and body forces due to passenger movements; Ⅱ Air conditioning outlet. The air flow near the air conditioning outlet is a relatively uniform inflow flow, which is regarded as an inlet boundary condition. The inlet velocity is determined according to the setting of the air conditioning system. The air velocity in this area is equal to the velocity of the external environment, which is expressed as: ； in, is the velocity vector at the inlet, is the unit normal vector pointing to the inlet, is the velocity magnitude at the inlet; Ⅲ Door area: the door area is set as an open boundary to simulate the open state of the door and allow air to flow freely, or it is set as a boundary connected to the external environment to determine the air flow according to the air pressure and temperature of the external environment; ； in, is the air velocity in the door area, is the air pressure in the door area, is the dynamic viscosity of air, is the density of air, is the acceleration due to gravity, is the volume force in the door area, including the airflow from the opening and closing of the window; IV. Luggage compartment area: the luggage compartment area is set to be a solid wall similar to the bottom of the cabin area, the velocity is zero, and the pressure is determined according to the external environment and the pressure of the gas inside the luggage compartment; Solid wall conditions: ； in, is the normal vector of the trunk area exit; Ⅴ Engine compartment area. The engine compartment area is located at the front of the vehicle. The boundary conditions need to take into account the impact of engine exhaust gas on air flow. The engine exhaust gas produces a velocity field on the air flow. , the exhaust gas velocity field is a Gaussian model; ； in, is the velocity of the exhaust gas, is the location of the discharge port, is the standard deviation of the Gaussian function, is a unit vector, used to indicate the direction of velocity; Using the above-mentioned Gaussian model, the flow of exhaust gas in the engine compartment area is obtained, and then the volume force generated by the exhaust gas is calculated to describe the driving effect of the exhaust gas on the surrounding air; ； Calculate the volume force generated by the exhaust gas on the air flow, and obtain the driving effect of the exhaust gas on the air flow by calculating the gradient of the exhaust gas velocity field; The momentum equation is used in combination with boundary conditions and initial conditions for calculation, and the following boundary conditions are considered; Solid wall condition, the solid part in the engine room is regarded as a solid wall, and the velocity is zero, that is, the velocity on the solid surface in the engine room is zero: ； The inlet boundary condition uses the velocity field of the exhaust gas as the inlet boundary condition to describe the effect of the exhaust gas on the air flow: ； The outlet boundary condition describes the air outflow with the pressure or velocity field at the outlet. The pressure at the outlet does not change along the normal direction, the pressure is uniform in this direction, and the pressure gradient at the outlet is zero, then: ； in, is the normal vector of the outlet boundary. The zero pressure gradient ensures that there is no flow driven by the pressure gradient at the outlet, and the fluid will not accelerate or decelerate in this direction; The initial velocity field and initial pressure field are set according to the vehicle motion state or experimental data; ； The momentum equation is: ； Among them, the left side is the inertia term and convection term of the air, and the right side is the pressure gradient term, viscosity term, external volume force term and exhaust gas volume force term. Combined with the boundary conditions and initial conditions, the impact of the engine exhaust gas on the air flow and the specific conditions of the air flow are calculated.

2. A portable rapid vehicle health detection device using an olfactory chip according to claim 1, characterized in that: In the air quality model, for the trunk area, the diffusion coefficient is greater than that of the other three areas except the air-conditioning outlet area, and the convection velocity is smaller than that of the other three areas except the air-conditioning outlet area, and the source term is zero; for the air-conditioning outlet area, the diffusion coefficient is greater than that of other areas, and the convection velocity is smaller than that of other areas.

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