Direct injection technique in automobiles involves injecting fuel directly into the combustion chamber, enhancing fuel efficiency compared to traditional carburetors. This method requires advanced injectors capable of withstanding high temperatures and pressures, resulting in higher production costs. Unlike conventional fuel injection that occurs during the intake stroke, direct injection occurs during the combustion stroke, reducing pre-ignition issues in high-compression engines. Additionally, it necessitates precise timing and control through computer systems, further increasing complexity and expense. Overall, direct injection represents a significant advancement in fuel delivery technology for modern gasoline and diesel engines.