Liquid fuel engines are a type of propulsion system that use liquid fuels, such as gasoline or kerosene, to generate power. These engines mix fuel with an oxidizer, typically air, and ignite the mixture to produce high-pressure gases. This rapid expansion of gases pushes against engine components, creating thrust or mechanical energy. Commonly found in vehicles like cars and airplanes, liquid fuel engines are known for their efficiency and power. They can be designed for various applications, from small engines in motorcycles to large engines in commercial aircraft. The technology behind these engines has evolved significantly, improving performance and reducing emissions over time.