Environmental pollution has always been the focus of everyone's attention, in order to alleviate the air pollution caused by motor vehicle emissions, in recent years, countries around the world are competing to develop new energy vehicles. Although new energy vehicles have been greatly developed, the application of internal combustion engines fueled by gasoline and diesel is still dominant at this stage. How to effectively control automobile pollution is still a global concern and an urgent problem to be solved.
In order to escort the environment, various environmental protection regulations and standards have been introduced around the world. For the mainland, the Ministry of Environmental Protection, the General Administration of Quality Supervision, Inspection and Quarantine and other relevant departments have also formulated standards for engine emission testing, determined emission limits and detection methods, and also put forward new demands for related instruments and technologies. In view of this, major instrument manufacturers have also entered the game in equipment development and contributed their own strength to the development of the industry. Especially in view of the market situation of China's scientific instruments, a number of domestic instrument manufacturers are constantly making breakthroughs, committed to improving the level of instruments and core key components, and realizing high-end domestic substitution. This paper will analyze the relevant regulations and equipment and market status of continental engine emission detection, and share the work and achievements of domestic instrument companies in instrument deep ploughing by Sifang Optoelectronics as an example.
Environmental protection policies are strictly controlled, and engine emission testing is becoming more and more stringent
Environmental regulations and standards are the main means of controlling pollution emitted by motor vehicles. At present, the emission standards of vehicles formulated by countries around the world are mainly divided into three major systems: European emission regulations, US emission regulations and Japanese emission regulations. European standards are implemented by the Economic Commission for Europe (ECE) vehicle exhaust emission regulations and the European Union (EU) vehicle exhaust emissions directive; the United States vehicle emission regulations can be divided into federal emission regulations, namely the Environmental Protection Agency (EPA) emission regulations and the California Atmospheric Resources Agency (CARB) emission regulations, and other states can choose to use California regulations or use federal regulations according to their own needs; Japanese regulations began to be implemented in the late 1980s; 2005, Japan has begun to implement new vehicle emission standards, and emission limits are much stricter than before.
The Ministry of Environmental Protection of the Mainland and the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China have formulated, issued and implemented a series of environmental protection regulations and standards to control the emission pollution of motor vehicles, and the emission regulations are becoming increasingly stringent. From May 1, 2019, GB 18285-2018 "Gasoline Vehicle Pollutant Emission Limits and Measurement Methods (Double Idle Method and Simple Working Condition Method)" and GB 3847-2018 "Diesel Vehicle Pollutant Emission Limits and Measurement Methods (Free Acceleration Method and Loading Deceleration Method)" were implemented from May 1, 2019, and GB 17691-2018 "Pollutant Emission Limits and Measurement Methods for Heavy-duty Diesel Vehicles (China Phase VI)" was implemented from July 1, 2019. From July 1, 2020, GB18352.6-2016 "Emission Limits and Measurement Methods for Light Vehicles (China Phase VI)" will be implemented; HJ 1014-2020 "Technical Requirements for Emission Control of Non-road Diesel Mobile Machinery" will be fully implemented by the end of 2022 to prevent and control the environmental pollution of non-road diesel mobile machinery exhaust pollutants and further improve the ambient air quality. The implementation of these regulations and standards has brought greater opportunities and challenges to relevant enterprises in the field of emission testing in China.
Imported instruments and equipment monopolize the market, and small and medium-sized engine enterprises are overwhelmed
The development of new automotive products and the research of new emission control technologies are inseparable from automotive emission detection systems. Correctly detecting the content of harmful emissions in automobiles is an important prerequisite for studying the formation of harmful emissions in automobiles and their control technologies and devices. With the increasingly stringent emission standards of automobiles in various countries, the relevant emission detection technologies have also been continuously improved.
In the field of vehicle emission detection and control, according to the application can be divided into three categories: (A) engine, vehicle emission research and type certification for emission testing equipment, referred to as the fixed capacity sampling system (CVS) or direct production emission analysis system and portable emission detection system (PEMS) ;(B) engine combustion and pollutant detection and control sensors, mainly high-temperature O2, NOx and SOOT sensors; (C) detection and maintenance of aftermarket I/M station emission testing equipment. In addition to the C class emission detection equipment in recent years through the use of imported and localization of the exhaust gas platform combined with dynamometer and other basic localization, A class emission detection equipment and B class large-scale, high-priced emission detection and control sensors (O2 sensor annual demand of nearly 100 million, NOx and SOOT sensor price of nearly 1,000 yuan each), almost all rely on imports.
High-end automotive emission detection equipment for emissions research and certification is different from the general analytical instruments, which includes core modules such as infrared gas detection, chemiluminescent or ultraviolet gas detection, heated FID and even online chromatographic gas detection, gravimetric or optical particle quantity PN and mass PM detection, CVS exhaust flow detection or high humidity transient exhaust gas flow detection. At present, few enterprises in the domestic analytical instrument industry have multiple sensor technology platforms in the field of gas analysis and professional knowledge of engine emission detection at the same time, so it is difficult to achieve this high-end automobile emission detection equipment that requires both high technology and high integration.
Engine combustion and pollutant detection and control O2 and NOx sensors are important components of the combustion control and exhaust gas aftertreatment system of gasoline vehicles and diesel vehicles, the ultimate temperature difference test of high-temperature ceramic chip raw materials, the production and packaging process of HTCC chips, and the software measurement and control of sensors have very high requirements for the company's technology research and development capabilities. At present, the domestic market is mostly monopolized by foreign manufacturers, and the procurement cost of domestic enterprise users is high.
Each breakout promotes the localization process of the whole industry of engine emission detection equipment
In view of the current situation, major domestic instrument companies are also going all out to promote the localization process of the entire industry of engine emission test equipment with practical actions. In particular, it is worth mentioning that Sifang Optoelectronics (stock code 688665), a listed company on the Science and Technology Innovation Board, independently completed the research and development and production of laboratory emission testing systems and portable emission detection systems (PEMS) for road testing in view of the current situation of domestic engine emission testing equipment and corresponding market demand, forming a emission testing system from the engine laboratory, portable emission testing equipment, and I/M station testing equipment. Complete solution for engine emission detection with O2 and NOx sensors for end-user automotive engine exhaust aftertreatment systems.
Engine laboratory emission detection system: realize the circulation test of exhaust pollutants
According to the National V and China VI standards, the new engine should be tested on the dynamometer bench for the circulation test of exhaust pollutants. The engine laboratory emission detection system can achieve an approximate simulation of the exhaust gas entering the atmosphere of the engine in accordance with the procedures specified by regulations and standards, and complete the sampling and detection of emission gases. The detection system requires continuous measurement of the concentration and exhaust mass flow of gaseous pollutants and dusts such as CO, CO2, NMHC (non-methane total hydrocarbons), NOx, etc., and records them in a computer system, requiring the integration of multiple gas sensing technologies.
Based on the combined advantages of the core gas sensing technology platform, Sifang Optoelectronics independently developed the engine emission full-flow dilution volume sampling system (CVS) as a high-end value-added application of the sensor, which has good stability and a system error of less than 2%. Used in conjunction with the gasboard-9801 engine direct production system, it can meet the requirements of the emission regulations GB 18352-2016 for light gasoline vehicles, GB 17691-2018 for heavy-duty commercial vehicles and motorcycle-related emissions.
Figure: Gasboard-9801, Sifang Photoelectric Engine Emission Detection System
Figure: Sifang photoelectric engine emissions full-flow dilution volume sampling system (CVS) Gasboard-9802
PEMS Portable Emission Detection System: Measures the pollutant emissions of the vehicle during actual driving
Before the National VI standard, the new engine or new model in the type certification stage, mainly based on laboratory data to verify whether the exhaust emissions meet the standard, but the engine in the laboratory operating state and the actual road driving state there is a big difference, laboratory data may not truly reflect the actual emissions of the engine. In order to solve the above problems, the National VI standards for mainland heavy vehicles have increased the engine portable emission detection system (PEMS) test, that is, the engine portable emission detection system is installed on the actual road driving vehicle, and the pollutant emissions of the vehicle in the actual driving process are measured. The China VI standard requires all engines and cars that require type inspection to undergo the above testing, and only new cars that pass the test can be produced, imported, sold and put into use or registered.
HJ 1014-2020 "Technical Requirements for Pollutant Emission Control of Non-road Diesel Mobile Machinery" issued on December 28, 2020 requires that from December 1, 2022, all non-road mobile machinery and diesel engines produced, imported and sold of 560KW (including 560KW) and installed diesel engines must comply with this standard. The standard is in addition to the fourth phase of the GB 20891-2014 "Limits and Measurement Methods for Diesel Exhaust Pollutants for Non-road Mobile Machinery (China Phase III and IV)" promulgated in 2014. The release of this standard has set an alarm clock for domestic non-road machinery OEMs, and the preparation of China IV products has officially entered the countdown stage. Compared with the original standard, one of the most important is to increase the limits and test procedures for on-board inspection by the vehicle method, and to stipulate the relevant technical requirements of the vehicle portable emission detection system (PEMS).
In view of the urgent needs of portable emission detection system (PEMS) in China, Sifang Optoelectronics quickly organized a research and development technical team to tackle key problems and realized the localization of portable emission detection system (PEMS). Gasboard-9805 series is a portable emission detection system (PEMS) specially developed by Sifang Optoelectronics based on the core gas analysis technology independently developed by Sifang Optoelectronics, which is used for non-road and road (light vehicles and heavy-duty diesel vehicles), which can realize CO, CO2, NO, NO2, THC emission concentration measurement, as well as particulate matter, exhaust flow, GPS data, ambient temperature and humidity, and atmospheric pressure measurement, and has test process guidance, automatic calculation of total emissions, Export test reports and other functions. In addition, the product adopts modular design, and the portable battery supports more than 6 hours of battery life to meet the requirements of on-board emission detection in the car in use.
Figure: Sifang Optoelectronic Portable Emission Detection System (PEMS) Gasboard-9805
On-board O2/NOx sensors: engine combustion and contaminant detection and control
The operation of fuel engines will release NOx, and the nitrate formed by this type of gas is one of the important causes of air pollution, and NOx has become a focus of air pollution control in recent years. As the main control technology of NOx nitrogen oxides, SCR is fully popularized in China VI diesel engines. The nitrogen oxygen sensor participates in the closed-loop control of the ammonia injection system and is the core sensor of the engine emission system.
The mainstream purification method for gasoline vehicle exhaust pollutants is to use a three-way catalytic converter to convert harmful gases such as CO, NOx, HC into harmless gases and water, and the level of purification efficiency depends on whether the concentration of the mixture is kept near the theoretical air-fuel ratio. Since the change in the air-fuel ratio will cause a corresponding change in the oxygen concentration in the exhaust gas, by setting an O2 sensor in the exhaust pipe, the O2 sensor can detect the oxygen concentration and feedback the signal to the electronic control unit of the car. The electronic control unit adjusts the amount of fuel injection in time according to the feedback signal, so that the air-fuel ratio of the mixture is kept near the theoretical value.
With the promulgation and gradual implementation of the "China VI" standard, the O2 and NOx sensor front-loading and post-installation markets continue to expand, and the annual demand of the front-loading market alone has reached 10 billion yuan. However, at present, the main market share is occupied by overseas manufacturers, and domestic demand is heavily dependent on imports. Now, in order to reduce the dependence on foreign manufacturers, domestic enterprises must independently develop O2, NOx and SOOT sensors for engine combustion and pollutant detection and control.
With years of technological innovation, lean production, quality control and other hard strength in the field of intelligent gas sensors, based on its own technology platforms such as high-temperature co-firing ceramics (HTCC) and high-temperature sensor packaging, Sifang Optoelectronics has realized the self-made core component chips required for sensors, built the component chips, packaging and sensor production lines required for sensors, and realized mass production. Through the integration of upstream and downstream supply chains and the independent production of core key components, Sifang Optoelectronics provides customers with the most optimized engine supporting O2, NOx and particulate matter sensor product solutions to achieve import substitution.
Figure: Four-way photoelectric O2/NOx/SOOT sensor
Sifang Optoelectronics' entrepreneurial team comes from Huazhong University of Science and Technology. Deputy General Manager Dong Pengju graduated from Huazhong University of Science and Technology majoring in internal combustion engines and has rich work experience in the automotive and engine industries. Dong Pengju told reporters that as a listed company on the Science and Technology Innovation Board, the development strategy of Sifang Optoelectronics has always been centered on serving key national industries and important needs. In the future, Sifang Optoelectronics will continue to increase the research and development and industrialization of engine emission detection equipment and vehicle core gas sensors. On the one hand, the company will continue to improve the engine laboratory capacity sampling CVS and direct procurement system, PEMS portable detection system, and I/M station emission detection equipment localization alternatives; on the other hand, Sifang Optoelectronics will provide O2, NOx and SOOT sensor products with higher reliability performance for the aftermarket, and win the "breakthrough battle" of engine emission detection equipment.