244000383 - CONSTRUCTION SPECIFICATIONS
The methane (or CNG) is stored, compressed at a pressure of 200 bar, in a series of red coloured canisters that are filled by means of a special filler which has a one-way valve.A solenoid valve, located on each canister, cuts off the flow of methane to the fuel supply system when the engine is not running.The methane, at high pressure, reaches the single stage pressure reduction unit via a pipe where the pressure is reduced to a constant value of 9 ± 1 bar.The methane is directed from the pressure reduction unit to the methane distribution manifold to which the special injectors are connected, each of which injects methane into the intake manifold of one cylinder, upstream of the inlet valves.The specific methane fuel supply system components are:- methane pressure sensor on the high pressure line;
- methane injectors
MEHTANE FILLER
The methane filler (1) is located on the left side panel near the driver''s door and is fitted with a dual one-way valve: one fitted in the actual filler body and the other near the canister, at the beginning of the supply pipe.To gain access to the filler (1), remove the cap (2) undoing it in an anti-clockwise direction.It is completed by a one-way valve (5) fitted in the actual filler body (4) connected to the canisters by means of a high pressure pipe (6).The repressurizing filler profile is the Italian type. In the case of fillers with "Italian" type profiles where methane gas in other European countries needs to be used, a special adaptor for the NGVI profile must be fitted (available from Lineaccessori Fiat).
METHANE CANISTERS
Methane in a gaseous state is compressed at a nominal operating pressure of 200 bar at 15°C in the canisters secured under the floor panel of the vehicle. They have a capacity of 160 litres. When the pressurizing is completed, the methane inside the canister remains in a gaseous state.The canister is entirely made from steel and is legally required to withstand hydraulic tests at a pressure of 300 bar. | The methane canisters have been certified in accordance with European Regulation CEE110. The canisters should be inspected and tested every 3 years. The dealer should hand over a plate for each canister, together with the documentation, which contains the expiry date of the test (month and year). Those responsible for refilling the methane are not authorized to refill canisters where the expiry date has passed and the driver should be shown the plates to make sure that this cannot happen. To simplify this check there is a label on the inner wall of the fuel cap containing the expiry date. All canisters should be inspected and tested on this date (valid for Italy). |
- the name of the manufacturer of the canister;
- serial number;
- type of gas designed for (methane);
- nominal operating pressure (200 bar) and hydraulic test (300 bar);
- capacity of the canister in litres (160 litres);
- weight of the canister in kg (specific for each canister);
- Italian Republic emblem;
- canister test date (month/year).
CANISTERS FOR VERSION WITH INCREASED RANGE
In addition to the (three) canisters on the regular version, the "increased range" version has a further two tanks with a capacity of 76 litres that contain methane in a compressed gaseous state; this makes the total capacity of the system 236 litres.The two additional canisters are housed under the vehicle floor at the rear in place of the spare wheel housing and they are protected by a special steel guard.
METHANE CANISTER VALVE UNIT
The valve unit is fitted directly on the canister and has been designed to carry out the following functions safely:- methane canister filling,
- engine fuel supply.
- the outlet towards the engine is closed whilst the passage from the filler to the canister is open allowing the filling of the actual canister.
Solenoid valve operation
The solenoid valve (1) directly on the valve assembly has the main function of managing the flow of methane coming out of the actual canister, intercepting the outlet duct from the valve assemblyThe inlet duct, on the other hand, is fitted with a single-acting valve (3) which prevents the flow of methane from the canister to the filler (for improved safety, a second single-acting valve is fitted on the filler itself).The solenoid valve is electrically supplied by the ignition via a special relay and is earthed through the inertia switch.With the solenoid valve de-energized (engine switched off) the route towards the pressure reduction unit is closed and methane operation is possible.With the solenoid valve energized (ignition key in ON position and petrol/methane switch released), the route to the pressure reduction unit is open placing the canister in contact with the engine fuel supply system.The flow of methane towards the outside is prevented by the single-acting valve (3).Manual cut out valve (tap)
The valve unit is equipped with a manual methane cut out tap (2) located upstream of the solenoid valve (1). Opening/closing it either allows or prevents the escape or intake of methane from the canister and it is important if any servicing operations are being carried out on the system.Single-acting valve
The single-acting valve (3) is fitted in the valve assembly methane inlet duct and is designed to prevent the flow of methane from the solenoid valve to the filler (for improved safety, a second single-acting valve is fitted on the actual filler).Safety devices
In order to prevent excess pressure or the rapid draining of the canister, the valve unit is equipped with the following safety devices:- meltable pad (4).
- flow restricter (5).