对现代内燃机，汽油缸内直喷是一种使用在两冲程和四冲程循环汽油发动机的燃料喷射设备。汽油经由高压共轨油路直接喷入每个汽缸的燃烧室，而不是如同传统的多点电喷将燃料喷入进气歧管。早期的缸内直喷引擎有污染物质难控制的问题，可通过欧洲废气排放标准但不能通过美国的标准，2004年日本五十铃汽车率先制造出能通过美国废气排放标准的缸内直喷引擎，1997年意大利菲亚特汽车（FIAT）将燃料高压共轨直喷技术使用在柴油引擎上十分成功，因此2006年奔驰汽车将此技术使用在汽油缸内直喷引擎上，但对燃料加压的压力没有高压共轨柴油引擎那样高，能协助从喷油嘴喷出的汽油单位体积变得更小更易雾化即可，有助于省油与性能的提升，不过代价是PM2.5排放提高千倍，而且目前尚未有法规规定采用缸内直喷的汽油引擎汽车一定要加装微粒过滤器。

In non-Diesel internal combustion engines, Gasoline Direct Injection (GDI), also known as Petrol Direct Injection, Direct Petrol Injection, Spark Ignited Direct Injection (SIDI) and Fuel Stratified Injection (FSI), is a variant of fuel injection employed in modern two-stroke and four-stroke gasoline engines. The gasoline is highly pressurized, and injected via a common rail fuel line directly into the combustion chamber of each cylinder, as opposed to conventional multi-point fuel injection that injects fuel into the intake tract, or cylinder port. Directly injecting fuel into the combustion chamber requires high pressure injection whereas low pressure is used injecting into the intake tract or cylinder port.