Core Viewpoint - The transition from conventional fuel tanks to high-pressure fuel tanks is driven by stricter emission regulations and the need for better fuel vapor management in hybrid and electric vehicles [1][12][15] Group 1: Fuel Tank Types - Conventional fuel tanks maintain pressure equilibrium with the environment and are typically made of high-density polyethylene, which helps reduce vehicle weight and fuel consumption [1] - High-pressure fuel tanks are primarily made of metal, designed for hybrid vehicles, particularly PHEVs, and are equipped with additional components like a carbon canister and fuel tank isolation valve [5][7] Group 2: Emission Control Mechanisms - Conventional fuel tanks are equipped with a carbon canister to capture and store fuel vapors, which are then combusted in the engine to meet emission standards [3][8] - The carbon canister's capacity is limited, and it operates effectively in vehicles with frequent engine operation, creating a closed-loop system of vapor absorption and combustion [3][8] Group 3: Advantages of High-Pressure Fuel Tanks - High-pressure fuel tanks prevent fuel vapor overflow and ensure compliance with emission regulations, especially during prolonged electric vehicle operation when the engine does not run [13] - Vehicles with high-pressure fuel tanks do not require regular engine starts to manage fuel vapors, enhancing user experience by avoiding unexpected engine activation during electric driving [15] - With the upcoming implementation of stricter emission standards, high-pressure fuel tanks are expected to become the standard, gradually replacing conventional tanks [15]