an engine and in this embodiment receives fuel provided by fuel lines 157 158 fuel and air mixed within the nozzle are expelled via an outlet 159 located at end 156 notably housing 152 incorporates housing openings e g opening 160 that permit air to flow from the exterior of the housing to the interior 162 of the housing for mixing with the fuel as shown in fig4 airflow to the interior of the housing is controlled by valve 170 which also incorporates valve openings e g opening 172 in the open position of the nozzle valve 170 is controlled so that openings of the valve align with openings of the housing in contrast in the closed position of the nozzle valve 170 is controlled so that openings of the valve do not align with openings of the housing thereby restricting the flow of air into the nozzle in particular when engine power reduction is required fuel is reduced at a predetermined setting fuel is shut off to a nozzle and valve 170 is closed fuel is redistributed among the open nozzles and or partially open nozzles simultaneously air also is redistributed among the nozzles that are at least partially opened notably fig4 depicts an intermediate position i e partially opened in which the openings of the valve are partially aligned with openings of the housing this tends to promote lower exhaust emissions at reduced power settings positioning of valve 170 is controlled by providing pressurized fluid to one side or the other of a piston head 180 that is housed.