The fuel injection and spray system comprise of a common-rail type high-pressure injection
pump (Haskel, HSF-300), an injector driver (TEMS, TDA-3200H), an electronically controlled injector with six holes, a digital delay generator (Berkeley Nucleonics Corp, 555), a high-pressure visualization chamber with optical windows, in which ambient pressure was varied using pressurized Nitrogen, and a data acquisition system with image grabber.