Introduction to the Results: Currently, a vast majority of vehicles in use in our country are equipped with carburetor engines. Converting carburetor gasoline cars into LPG-gasoline dual-fuel vehicles can not only reduce the emissions of pollutants from vehicle exhaust but also improve the energy structure of automobiles. This achievement has adopted an LPG gas supply system for existing vehicles and added an electronic control air replenishment device and a three-way catalytic converter. Through extensive engine bench tests and whole vehicle bench matching tests, it has been demonstrated that the modified vehicles can meet the 'Shanghai Light-Duty Vehicle Exhaust Emission Standards' (DB31/29 - 1998) when using either fuel separately. It features high domestication rate, simple structure, convenient modification, and low cost, making it particularly suitable for carburetor-engine sedans. Functional Characteristics: (1) LPG-gasoline dual-fuel sedan modified from the carburetor-type ordinary Santana (after using LPG) Emission of pollutants Idle speed method The emissions of pollutants at idle speed for this LPG-gasoline dual fuel sedan comply with the requirements of GB14761.5-93 'Gasoline Vehicle Idle Speed Emission Standards'. CO emissions are below the standard limit by 78%, and HC emissions are below the standard limit by 83%. However, compared to using gasoline, CO emissions have decreased by 20.7%, while HC emissions have increased by 53%. Fifteen working condition method CO emissions are below the standard limit by 40.3%, and HC+NOx emissions are below the standard limit by 20.5%. Compared to burning gasoline, CO emissions have decreased by 34%, and HC+NOx emissions have decreased by 6%. Other performance The crankcase pollutants, starting performance, power, durability, exterior noise, and fuel economy of the dual fuel sedan all meet enterprise standards. However, after switching to LPG, the power performance is slightly lower than when using gasoline. The Santana 2000 model LPG-gasoline dual fuel sedan (after using LPG) has the following emissions characteristics: 1) Emissions at idle speed: The emission levels of pollutants from this LPG-gasoline dual fuel sedan meet the requirements of GB14761.5-93 'Gasoline Vehicle Idle Speed Emission Standards'. CO emissions are below the standard limit by 80.3%, and HC emissions are below the standard limit by 78.3%. However, compared to gasoline use, CO emissions have decreased by about 40%, while HC emissions have increased by 27%. 2) Other performance: The crankcase emissions, starting performance, power, durability, exterior noise, and other aspects of the dual fuel sedan are as follows: - Crankcase emissions: The emissions from the crankcase meet the standards for both gas and diesel engines. - Starting performance: The vehicle can start smoothly under normal conditions without any special procedures or adjustments. - Power: The engine provides sufficient power for normal driving, with no significant differences in performance between gasoline and LPG modes. - Durability: The vehicle is designed to withstand regular maintenance and service intervals, ensuring long-term reliability and durability. - Exterior noise: The vehicle complies with the relevant noise emission standards, ensuring a quiet and comfortable driving experience. Fuel economy meets the enterprise standards. However, power performance is slightly lower when using LPG compared to gasoline. (3) The carburetor-type ordinary Santana equipped with an electronic control air supply and a three-way catalytic converter for LPG-gasoline dual fuel sedan (using LPG): 1) Emission pollutants at idle speed: The emission of pollutants from this LPG-gasoline dual fuel sedan during idle speed testing complies with the requirements of DB31/23—1999 'Light-duty Vehicle Dual Idle Speed Emission Limits and Test Methods'. Low idle speed: CO emissions are essentially zero, HC emissions are below the standard limit by 95%; high idle speed: CO emissions are below the standard limit by 95%, HC emissions are below the standard limit by 98.3%. European 83—01 regulation (without considering degradation factors) C0 emissions are below the standard limit by 72.4%, HC + NOx emissions are below the standard limit by 6.3%. Compared with the test results of a similar dual-fuel sedan without a three-way catalytic converter and an electronic control air supply device (Section 1), when burning gasoline, CO decreased by 95.0%, HC + NOx decreased by 78.1%; when burning LPG, CO decreased by 84.4%, HC + NOx decreased by 79.8%. (2) The power performance and fuel economy of other dual-fuel sedans have met the enterprise standards. However, after using LPG, the power performance is slightly lower than that of using gasoline. (4) The Santana 2000 model equipped with an electronic control air supply and a three-way catalytic converter for gasoline-LPG dual-fuel sedan (after using LPG) 1) Emission pollutants Idle speed method The emission pollutants of the gasoline-LPG dual-fuel sedan at idle speed after using LPG comply with the requirements of DB31/23 -1999 'Light-duty Vehicle Dual-Idle Speed Emission Limits and Test Methods'. Low idle speed: CO emissions are below the standard limit by 33-96%, and HC emissions are below the standard limit by 25-62.5%. High idle: CO emissions are below the standard limit by 25-90%, and HC emissions are below the standard limit by 33.3-66.6%. Compared to using gasoline, CO and HC emissions are essentially consistent. According to the European 83-01 regulations (without considering degradation factors), after burning LPG, CO emissions are below the type approval limit by 55.9%, and HC + NOx emissions are below the limit by 2%. Compared to the test results of a similar dual-fuel sedan without a three-way catalytic converter and electronic controlled air replenishment device (section (2)), when burning gasoline, CO emissions decrease by 87%, HC + NOx emissions decrease by 80.9%; when burning LPG, CO emissions decrease by 88.3%, and HC + NOx emissions decrease by 78.1%. The power and fuel economy of other dual-fuel sedans have met the enterprise standards. Application field: Two out of four prototype vehicles have entered the national automobile product catalog. By using a single module electronic control air supply device and a three-way catalytic converter, carburetor-type LPG-gasoline dual-fuel sedans can meet the latest national standards (equivalent to European I standard) when using LPG and gasoline respectively, achieving a leading level in China. This achievement can be promoted to all sedans and light-duty vehicles equipped with carburetor engines.