Reducer Working Principles

ompressed Natural Gas flows from the tank to reducer through a special inlet nipple
(1). A filter (2) avoid solid particles to get into the reducer. 1st Reduction stage. The
High Pressure Valve (3), is controlled by High Pressure Membrane (4), this regulates
gas flow in the double Chamber of heating and expansion (5), where pressure is reduced
till 180 kPa. From here gas flows to the 2nd reduction stage. 2nd Reduction stage. It is
constituted by a Chamber (6), in comunication with the mixer, placed upstream the
throttle valve. The Membrane Unit (7), through the Valve (8) actuated by the Membrane
(9), feel the suction generated by engine pistons. The Valve (10), controlled by the just
mentioned unit, regulates gas flow from 1st stage Chambers (5) to 2nd stage Chamber (6),
where pressure is furtherly reduced till atmospheric (0±20 Pa). From here, gas flows into
intake manifold where it mixes with air coming from engine air filter, before flowing
inside cylinders ignition chamber.



“Stabilizer” device. The Stabilizing Valve (12) is controlled by the Membrane (11).
This valve permit to optimise the gas flow to the engine independently from engine rpm
values and from gas tank pressure. Shut off valve. A solenoid valve (19), controlled by
gas/petrol switcher, cuts gas flow from 1st to 2nd stage, at the same time the engine is
switched off. This happens both in case of intentional and casual switching off (in case
of damaging, accident, fuel completely consumed, etc. Heating system: CNG expansion
due to pressure reduction, has the effect of a temperature reduction. To avoid icing
inside the reducer, and to get the best efficiency from the fuel, the chambers where gas is
expanding, are heated up by engine cooling liquid (13). Carburetion adjustment
screws. Beside reducer there are 2 adjusting screws. The hexagonal M10 screw is the
Offset adjusting screw (14) and allow to modify the delivered gas quantity. The
hexagonal M8 screw is the Idle adjusting screw (15) and it’s usually closed. It must be
unscrewed only in the case the engine is switching off, in case of strong braking or fast
bend.