改写这段话：改造后的二冲程煤油直喷发动机采用低压空气辅助缸内直喷方式供油。空气辅助缸内直喷系统的核心是空气辅助喷油器由三部分构成：喷油器、喷气阀和空气腔如图23所示。喷油器的主要作用是计量燃油并将具有一定压力的燃油喷入空气腔。喷油器喷出的燃油在空气腔中进行第一次雾化形成的混合气由喷气阀喷入气缸。

The modified two-stroke diesel direct injection engine uses a low-pressure air-assisted in-cylinder direct injection method for fuel supply. The core of the air-assisted in-cylinder direct injection system is the air-assisted fuel injector, which consists of three parts: the fuel injector, the jet valve, and the air chamber, as shown in Figure 2.3. The main function of the fuel injector is to meter the fuel and inject it into the air chamber with a certain pressure. The fuel sprayed by the fuel injector undergoes the first stage of atomization in the air chamber, and the resulting mixture is injected into the cylinder by the jet valve