The principle of a vehicle exhaust remote sensing detection vehicle: Motor vehicles use remote sensing light sources to radiate ultraviolet and infrared rays onto an optical reflector on the opposite side of the road. The reflector then reflects the ultraviolet and infrared rays back to the detector. As the car travels along the road, it passes through these rays. Because the car uses light, it changes the intensity of the transmitted light. Therefore, by detecting changes in light intensity in the detector, the concentration of nitrogen oxides, hydrocarbons, and carbon monoxide emitted by the vehicle on the road is monitored. Remote sensing also monitors the relative concentrations of pollutants such as CO2, HC/CO2, and CO/CO2 in automotive fuel. Based on this, concentration equations for various types of compounds are derived and calculated. Therefore, if the vehicle is in a stoichiometric air-fuel ratio combustion state, good remote sensing results can be achieved.
The exhaust gas remote sensing monitoring system comprises two parts: a road traffic detection system and a road traffic speed limit system. The road traffic speed limit system is primarily used for remote sensing emission detection technology for motor vehicles. This system can simultaneously detect the exhaust emissions of diesel vehicles traveling in multiple lanes, providing accurate results. When a vehicle passes the remote sensing equipment, infrared, ultraviolet, and green laser light are simultaneously triggered, and the camera collects vehicle information. While capturing images, the system monitors and analyzes pollutants in the vehicle's exhaust, and the relevant data is quickly uploaded to the system's monitoring platform. In addition to real-time monitoring of indicators such as smoke opacity, carbon monoxide, carbon dioxide, hydrocarbons, and nitrogen oxides in truck exhaust, the system can also capture images of overloaded vehicles on the road. It provides real-time monitoring of whether the exhaust emissions of motor vehicles on the road meet emission standards.
In recent years, with the rapid development of my country's automobile industry, the number of motor vehicles has increased dramatically, and vehicle exhaust has become one of the major sources of air pollution. Motor vehicles are powered by fuel, whether gasoline or diesel, and continuously emit exhaust gases during combustion. These exhaust gases contain harmful components such as carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, and inhalable particulate matter. These pollutants are not only highly toxic, but can also interact to form secondary pollution.
Overview of the principle of motor vehicle exhaust remote sensing detection system
The vehicle exhaust remote sensing detection system mainly includes a telemetry host, a high-resolution speedometer, a comprehensive meteorological and environmental parameter monitoring system, an LED display screen, a main control computer, a printer, and control software for the vehicle exhaust remote sensing monitoring system. It is divided into two main categories: mobile and fixed. Fixed telemetry systems installed on main urban roads can measure passing vehicles horizontally or vertically (using a gantry). The ability to move measurement points and flexibly determine measurement points is an effective supplement to fixed-point telemetry measurements.
(1) Technical principles.
Motor vehicle exhaust remote sensing detection systems utilize a light source to project ultraviolet and infrared light onto the opposite road surface, which is then reflected back to the detector via an optical mirror. As vehicles travel on the road, they pass through this light. Because vehicle exhaust absorbs light, it alters the intensity of the transmitted light. Therefore, by detecting changes in light intensity at the detector, the concentrations of nitrogen oxides, hydrocarbons, and carbon monoxide emitted by vehicles on the road are monitored. Motor vehicle exhaust remote sensing detection systems primarily measure various relative concentrations such as NO/CO2, HC/CO2, and CO/CO2. The concentrations of various gases in the exhaust are calculated using specific formulas. Therefore, if the vehicle is operating under stoichiometric air-fuel ratio combustion conditions, good remote sensing results can be achieved.
This invention eliminates the need for contact with the vehicle being tested, enabling rapid identification of heavily polluting vehicles and monitoring their acceleration, deceleration, and driving characteristics, effectively avoiding the impact of abnormal operation on the test results. The system can record a certain amount of vehicle emission-related data on a computer, such as vehicle model, manufacturer, owner, and production year, thereby determining whether the vehicle has emission control issues. It utilizes tunable diode (TDL) lasers for remote sensing monitoring of vehicle exhaust, thus expanding the detection range for specific gas concentrations.
(2) System advantages.
Employing tunable semiconductor laser absorption spectroscopy, ultraviolet absorption spectroscopy, weak signal detection, and image recognition technologies, this system enables the detection of CO, CO2, NO, HC, and opacity in automotive exhaust gases, with a short response time (less than 0.8 seconds). The detection signal, transmitted via Wi-Fi, can be connected to an external LED display screen to show automotive exhaust emission information. The system also features: 1. High on-site deployment efficiency; 2. Narrow-wave radar speed; 3. Integrated calibration system; 4. Real-time data pairing; 5. Remote online monitoring system; 6. Automatic recording and storage.
Currently, the enforcement model for excessive vehicle exhaust emissions in my country mostly relies on manual vehicle interception and monitoring, with traffic police issuing penalties. This method is not only affected by weather and environmental factors but also suffers from low enforcement efficiency and unsatisfactory penalties. To address these issues, a new technology has emerged—the all-laser remote sensing monitoring system for vehicle exhaust emissions.
All-laser remote sensing monitoring of vehicle exhaust emissions is a scientific, efficient, convenient, and easy-to-operate method for exhaust emission detection. The system mainly consists of a light source transmitter/receiver, a video license plate capture system, a reflector, and a speed/acceleration detection system.
Composition of the all-laser vehicle exhaust remote sensing monitoring system
Light source transmitter/light source receiver:
The outer casing is treated with sandblasting for corrosion protection, and the entire assembly is fully enclosed, unaffected by harsh environmental factors. Six near-infrared lasers measure oxygen, hydrogen, carbon monoxide, and carbon dioxide respectively; a mid-infrared laser detector measures hydrocarbons and nitrogen oxides; and a green laser measures particulate matter opacity, smoke factor, and light absorption system.
Video license plate capture system:
High-definition video recognition devices mainly include high-definition cameras, lenses, supplementary lights, license plate recognition software, transmission systems, and central application systems. They analyze captured images and recognize license plates.
Reflecting end:
The light source reflector uses a high-hardness sapphire mirror and has a built-in shock absorption device for strong pressure resistance. The specially designed materials and installation process make the reflector suitable for various road sections and will not be damaged by the running over and scraping of various vehicles, thus ensuring reduced light source loss.
Speed/acceleration detection system:
The speed/acceleration monitoring system uses the principle of light cutting to accurately calculate the vehicle's speed/acceleration, vehicle length, and height, providing more sufficient conditions for judging the reliability of vehicle data.
Detection principle
The system emits ultraviolet and infrared light through a laser telemetry host, which is reflected into the detector by an optical mirror. When a vehicle passes through a road equipped with the device, the exhaust gas from the vehicle absorbs the light and changes the intensity of the transmitted light. The detector monitors the changes in light intensity to determine the concentration of nitrogen oxides, carbon oxides, and hydrocarbons passing through the vehicle.
Advantages of the system
1
Advanced measurement principle
A complete laser measurement system is used for various species, resulting in significantly higher accuracy than traditional methods. The optical path is no less than 26 meters, enabling long-distance detection.
2
Automatic real-time temperature and pressure compensation
It monitors ambient temperature, pressure, and local concentration in real time. It automatically performs real-time temperature and pressure compensation through a built-in temperature and pressure matrix.
3
Reduce labor costs
It can achieve simultaneous monitoring of multiple devices and multiple channels on the same road section, without human intervention, saving labor costs.
4
Supports three-level networking
The national, provincial, and municipal three-level networked big data unified application platform operates an interconnected monitoring system, supports remote control and data transmission via the Internet, and allows operators to remotely monitor, operate equipment, query, extract, and manage data from any location.
The application of remote sensing monitoring systems for motor vehicle exhaust emissions has greatly improved the efficiency of urban motor vehicle environmental supervision and law enforcement. It enables precise control of high-emission vehicles, effectively controls and reduces the impact of motor vehicle emissions on the atmospheric environment, and severely cracks down on illegal activities such as driving high-emission vehicles on the road, thus safeguarding the improvement of urban ambient air quality.
As my country's vehicle emission standards are gradually upgraded, there will be significant differences in emission levels among various vehicles on the road. Effectively reducing vehicle emissions' pollution of ambient air quality and identifying and controlling high-emission vehicles are essential for improving urban air quality.
With the call that "lucid waters and lush mountains are invaluable assets," the control of motor vehicle exhaust pollution has received increasing attention, and remote sensing monitoring technology will undoubtedly play a greater role in this process.
