The new generation of HEUI21 February 1999
Caterpillar has developed a new generation of its hydraulically-actuated electronic unit injector (HEUI) fuel system product.
The HEUI-B fuel injection system uses a single solenoid to control the oil pressure to the intensifier, and the oil pressure to control the nozzle check. This is accomplished by precise hydraulic and event control of two valves, one acting as a pilot to the other. Neither valve depends on any sort of modulation during its travel to accomplish injection control.
The injectors operate independently of engine speed and load, and provide rate shaping to modify engine heat release characteristics. Electronics are used to tailor the engine's operating condition, thus optimising performance over the entire operating map.
The HEUI-B uses very high injection pressure at the nozzle. It currently achieves 1350 bar, and a target of 1850 bar has been set.