求翻译：　　2.由于汽油中的烯烃在燃烧后会形成胶质和树脂状的粘稠物。这些粘稠物在喷嘴、进气阀、燃烧室（气缸盖和活塞顶）等部位沉积就会变成坚硬的积碳。是什么意思？

2 olefins in gasoline combustion after the formation of gum and resin-like viscous material. The viscous material in the nozzle, the intake valve and combustion chamber (cylinder head and piston top) and other parts of the deposition will become hard carbon deposits.