two-spring injection-nozzle with needle-displacement sensor low fuel injection (the valve needle is lifted against the weak spring # 1) high fuel injection (the valve needle is lifted against stiff spring # 2) the needle-displacement sensor senses start of injection description ordernumber 291 see also: delivery valves single-acting fuel pump for DE (Diesel engines) volume controlling unit (in-line injection pump) exhaust gas recirculation / EGR