A hybrid inflator (10) for a vehicle passenger restraint system comprises a centre tie (14) having upper and lower ends (16, 18), and a curved, continuous vessel wall (20) secured to the upper and lower ends of and surrounding the centre tie to define a pressure chamber (26) storing inert compressed gas. The centre tie defines a combustion chamber (30) extending from the lower end thereof, the combustion chamber receiving pyrotechnic gaseous heat source material (31) and a squib (32) for igniting it. The centre tie further defines a directional inlet port (40) extending from the combustion chamber into the pressure chamber and a rupturable diaphragm (44) seals the inlet port until ignition of the pyrotechnic generant. The centre tie also defines a directional outlet vent (50) extending from the pressure chamber adjacent the upper end of the centre tie, the directional outlet vent being oriented substantially opposed the inlet port. The outlet vent is part of an outlet passage (53) from the pressure chamber through the upper end of the centre tie, including an orifice cavity (52) and outlet orifice (54), oriented to provide further turns in the gas flow path. A rupturable diaphragm (58) seals the outlet passage until ignition of the gas generant. A diffuser (62) provides an additional change of direction of the outlet path.