M.T.M. s.r.l.

                                                 Via La Morra, 1
                                          ...
2                                                            GUIDE TO CNG
1. GASEOUS FUELS                                ...
GUIDE TO CNG                                                                3


2. CNG:                                   ...
4                                                 GUIDE TO CNG
3. CNG                                    one. Therefore, w...
GUIDE TO CNG                                                               5


4. CNG                                     ...
6                                                               GUIDE TO CNG
ber that CNG pollutes little becau-          ...
GUIDE TO CNG                                                                        7


5. CNG SPREAD                     ...
8                                                GUIDE TO CNG
cultural field.                                             ...
GUIDE TO CNG                                                                            9


CNG EQUIPMENT                 ...
10                                                  GUIDE TO CNG
bodywork, and fix it with the suita-                     ...
GUIDE TO CNG                                                         11


Through the same passages, but in              H...
12                                                     GUIDE TO CNG
insulated from silencers and
exhaust gas ducts by mean...
GUIDE TO CNG                                                          13


    For fixing pipe to the car                 ...
14                                                GUIDE TO CNG
6.2.6.2. “VM A3/E” CNG valve                               ...
GUIDE TO CNG                  15



6.2.7. CNG MANOMETER                                     Pict. 23

                   ...
16                                                                GUIDE TO CNG
   As we already said in § 6.2,            ...
GUIDE TO CNG                                                                               17



6.3.2. TRADITIONAL REDUCE...
18                                          GUIDE TO CNG
working, we want to remember that                                ...
GUIDE TO CNG                                        19


   Clutch, blunted at 45°, will have                             ...
20                                      GUIDE TO CNG
6.3.3.3. Separate Venturi system                        Pict. 35

Sep...
GUIDE TO CNG                                                                      21



6.3.4. WIRING SYSTEM ON
CARBURETTO...
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
90 V99001011 Guida Metano En
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90 V99001011 Guida Metano En

  1. 1. M.T.M. s.r.l. Via La Morra, 1 12062 - Cherasco (Cn) - Italy Tel. +39 0172 48681 Fax +39 0172 593113 http://www.brc.it/ Guide to CNG Brc Gas Equipment gas systems for motor vehicles UNI EN ISO 9001:2000 Certified Company 90AV99001011 - N. 01 of 02.27.2004
  2. 2. 2 GUIDE TO CNG 1. GASEOUS FUELS Of course, they can’t be stocked intrinsic qualities, to the technologi- neither in the open air, nor in con- cal progress, to the geographical tainer with environmental tempera- growing of the markets and to the ture or pressure. discover of big deposits in West To increase its energy, with a Europe, Russia, North Africa and same volume stocked, it’s neces- Middle East. Today, it’s the third sary to compress or liquefy it, and world energetic source after oil and then stock it in thermo-insulating coal: every year, we consume more containers at a very low temperatu- than 2.400 billions cubic meters of re (for CNG - 180 °C). it, namely the 23% of the world Among the fuel classes, gathe- energetic request. red according to their aggregation 1.1. COMBUSTIBLES NATU- state in solid, liquid and gaseous RAL GAS In Italy, some big deposits have fuels, these latter are the freest These words indicate all natural been found under the Padana Plain from impurities, the most suitable to combustibles gases such as the alluvial layer, near Ravenna, in supply burners, combustion cham- fossil, the marsh, the volcanic and some areas of South Italy and in bers and furnaces, and they can the mine ones. Sicily. easily mix with air in stoichiometric Although largely diffused on or other required proportions. Earth, natural gas has been disco- Being in phase with air, they can vered and used just in recent times. easily create a complete combu- Natural gas became a largely stion with a little air excess. But this used energetic source just after the is the reason why they allow high ‘30s, that’s to say when develop- combustion efficiency and high ment of pipes building and placing flame temperatures. They are suita- technologies made possible use it ble for long-distance transportation as an “alternative” to the “city gas” by means of pipes, for a wide- coming from coal distillation. Since spread distribution, and for the easy that, natural gas diffusion has measure by single users. grown even more, thanks to its Pict. 1 Reserves and consumption of natural gas (Source SNAM) 415 710 6.500 640 6.500 Western Europe 180 Eastern North America Europe Middle East 11.500 55 Asia and 8.000 Africa Oceania 130 Central and South America Reserves and consumptions of natural gas Billion cubic meters World consumptions 1999 2.400 World reserves at 1.1.2000 155.000
  3. 3. GUIDE TO CNG 3 2. CNG: C N G MA I N C H A R A C T E R I S TI C S tion (5%) is higher than the petrol GENERAL Symbol: CH4 (1%) and the diesel oil (0,5%) one; Volume mass: 0,7172 kg/m3 this helps avoiding possible fires CHARACTERISTICS Density related to air: 0,5546 after an accident. Higher calorific power: 39,82 MJ/m3 Density and specific weight of Lower calorific power: 35,89 MJ/m3 gaseous CNG are lower than the Self-ignition temperature: 595 °C air ones (air = 1,29 kg/m3; CNG = Limits of flammability with percentage 0,7172 kg/m3), so, in case of leaka- volume in the air: ges, it tends to volatilize, rise and • Lower 5% disperse in the atmosphere, without CNG means COMPRESSED • Higher 15% stagnate in dangerous concentra- NATURAL GAS. tions at the ground level. We can consider natural gas as Thermic use of natural gas gives only made up of methane (CH4), many advantages in comparison CNG is flammable like ALL because the other hydrocarbons with the solid and liquid fuels: better fuels. So, it’s important to avoid such as ethane, propane, butanes, flame adjustment, big combustion their handling near naked flames or pentanes, carbon dioxide, a part of flexibility, absence of residuals and objects with a high temperature. nitrogen and helium, are normally corrosive components in the exhau- present in very low percentages. st gases. In Italy, methane quantity pre- It’s mainly used in the domestic sent in CNG changes in accordan- field, for producing electric energy ce with its origin (pict. 2): the gas and for chemical transformations. coming from Algeria has a low con- Unlike petrol and diesel oil, it tent (just 83,66%), while in the doesn’t need complicated refining national or Russian ones, we can processes to be extracted. Since its find higher percentages (more than origin, it’s ready to be used as eco- 98%). This is the reason why we logic fuel. usually identify Natural Gas with its CNG has the highest flash point, main component, calling it “metha- compared to any other fuel. Its self- ne”; but in this guide, we are going ignition temperature, in fact, is dou- to call it CNG. ble (595 °C) than the liquid fuels one, and its combustion concentra- G AS N a t i o na l Ru ssia n D ut c h A lg er ia n Pict. 2 Composition and A p p r o x i m at e c o m p o s i t i o n %m ol . % m o l. %m ol . % m o l. characteristics of CNG distributed in M e t h an e 99,62 98,25 92,66 83,66 Italy. E th a n e 0,06 0,54 2,95 7,71 (abstract from P ro pa ne 0,03 0,16 0,81 1,95 source SNAM). I s o -B u ta n e 0,01 0,03 0,11 0,28 N - B u ta n e - 0,03 0,16 0,41 I s o -P e n ta n e - 0,01 0,03 0,08 N - P e nt a ne - 0,01 0,03 0,08 H e x a ne s + 0,01 0,01 0,05 0,07 C a r bon di ox i d e 0,03 0,08 0,89 0,20 N i t ro ge n 0,24 0,87 2,28 5,40 H e l i um - 0,01 0,03 0,16 C h a r a ct e r i s t i c s P c s ( 1 ) k c a l/ S m 3 9.011 9.014 9.131 9.498 P cs ( 1 ) M J / S m 3 37,73 37,74 38,30 39,76 3 P c s ( 2 ) k c a l/ S m 8.113 8.118 8.234 8.583 3 P cs ( 2 ) M J / S m 33,97 33,99 34,47 35,94 (1) Higher calorific power. A v e r a g e m o l e c u l a r we i g h t 16,11 16,33 17,38 18,78 (2) Lower calorific V o l u m e t r ic m a s s k g / S m 3 0,6826 0,6921 0,7369 0,7964 power.
  4. 4. 4 GUIDE TO CNG 3. CNG one. Therefore, we suggest you IN AUTOTRACTION carefully realize the engine ordinary maintenance. In this way, you will (Technical aspects) obtain all benefits of the CNG sup- ply with the lowest costs. CNG doesn’t need anti-detona- ting additives because it has an octane number higher than the petrol one and equal to 120-125 (octane measures the anti-detona- ting power of a fuel, that’s to say its ability to avoid that mix ignition pro- vokes a detonation instead of a little combustion inside the cylinder). This ability makes possible to have higher performances than the petrol ones in dedicated engines (espe- cially planned for using CNG, so with a higher compression ratio). Combustion completeness insi- de the explosion chamber and per- fect thermic efficiency avoid incru- stations, particulate dust, residual deposits in the oil, and make possi- ble longer maintenance gaps and engine life. CNG vehicles excel also for easy maintenance; in fact, they don’t need special and expensive interventions. Thank to its proper- ties, natural gas has a very clean and complete combustion that impedes formation of residuals and incrustations, which could lead to the engine bad working and to the consumption increase in the midd- le- and long-term. In fact, is a mat- ter of fact that propellers of natural gas vehicles have a longer life and a more homogeneous efficiency compared to the petrol and diesel oil vehicle ones. Additional devices of the CNG equipment don’t need special maintenance, if vehicle is submitted to each normal car servi- ce suggested. Following the sugge- sted maintenance, the check of CNG supply can be made at a kilo- metrical gap bigger than the petrol
  5. 5. GUIDE TO CNG 5 4. CNG than its quantity in absolute values, ved, such as production stations IN AUTOTRACTION in order to establish its real noxiou- and battery disposal). sness (see table in picture 3). AND THE It’s important to remember that ENVIRONMENT In the USA, vehicles CNG sup- CNG doesn’t contain lead unlike ply is the less polluting at all, “premium petrol” doesn’t contain , thanks to their very severe legisla- sulphur unlike diesel oil and conse- tion about environment protection. quently emissions of Sulphur Oxide Table in picture 4 (source Bosch) of diesel engines; it doesn’t contain shows data detected by the PAHs (Polycyclic Aromatic The traffic increase influences “California Air Resources Board” Hydrocarbons), very dangerous more and more environment and centre, which compares emissions because the worst carcinogenic energetic consumptions negatively. of engines supplied with unleaded agents, presents in the unleaded Especially the transport sector is petrol and with other alternative and petrol. responsible for emissions of carbon today’s fuels, for what concerns CO oxide, nitrogen oxide, unbur nt (Carbon Oxide), HC (Unbur nt Graph in picture 5 (source hydrocarbons, lead, benzene, car- Hydrocarbons) and NOx (Nitrogen Bosch) shows pollution reduction bon bi-oxide, sulphurous anhydride Oxides). we can obtain with alternative fuels. and particulate dust (diesel) in the So CNG, together with LPG, Pollution is calculated using the environment. results the less polluting fuel, and “Californian system” that gives a only two future “fuels” as hydrogen “bonus” to each fuel in accordance Combustion is inevitably pollu- and electricity win it (but for these with its danger for the ozone. ting. Emissions coming from it are fuels, big problems about environ- connected to the fuel chemical and mental impact have still to be sol- At the end, we want to remem- physical properties and to the fuel- comburent mixture composition, but Pict. 3 also to the combustion working and C om p ou n ds T ox i c i ty to the environment characteristics. pa r a m e t e r s Every product of combustion CO Carbon Oxide 1 negatively influences air quality, but it’s more important to know toxic HC Unburnt Hydrocarbons 60 degree of every single element, NOX Nitrogen Oxides 100 Pict. 4 Fu el CO HC NOx CNG, together with LPG, results the less polluting Unleaded petrol (3-way catalyst) 100 100 100 fuel, and only two “future fuels” as Actual Diesel 20,48 80,93 152,27 hydrogen and electricity win it. Diesel (with catalyst for NOx) 20,48 80,93 143,16 Petrol (with “lean burn” supply) 15,87 9,51 145,44 (Source Bosch - Consorzio EcoGas) Petrol (2-stroke engine catalyzed for NOx) 14,59 10,09 51,87 Ethanol 15,43 9,47 53,18 Methanol 14,51 10,92 51,92 L.P.G. (with 3-way catalyst) 13,62 9,56 49,08 C.N.G. (with 3-way catalyst) 13,66 10,02 50,89 Electric 0 0 0 Hydrogen 0 0 9,12 Actual Alternative LPG and fuels fuels CNG
  6. 6. 6 GUIDE TO CNG ber that CNG pollutes little becau- CO - Carbon se: oxide - combustion happens during 160 HC - Unburnt the gaseous state, so being CNG a hydrocarbons gas in its natural state, it suits better 140 NOx - Nitrogen to this process assuring a more oxides homogeneous mixture with no 120 heavy particulate dust, - its higher thermodynamic cha- 100 racteristics make a better combu- stion easier, 80 - there are no additives such as 60 lead, sulphur and aromatics. 40 Moreover, BRC Gas Equipment proved that it’s possible to optimize 20 LPG combustion obtaining at the same time better performances and 0 Petrol with catalyst Diesel Diesel with catalyst for NOx “Lean Burn” petrol Petrol 2 stroke with catalyst for NOx Methanol Ethanol LPG or CNG Electric Hydrogen less pollution. In order to respect the more and more sever laws about environ- ment, some carburation control devices have been realized, such as the pioneering "BLITZ", “JUST” , Pict. 5 - Polluting emissions of the engines are obtained considering as 100 the emissions and “SEQUENT” which, submitted , values of unleaded petrol engine with catalyst. to various and hard anti-polluting (Source Bosch - Consorzio EcoGas) tests, have always given excellent results about emissions and perfor- “JUST” device “JUST HEAVY” device “SEQUENT” device with BRC ME reducer Skoda Octavia 2.0i - 85kW Ford Focus 1.8i 16V - 85kW mances (pict. 6). Opel Agila 1.2i 16V - 55kW Directive 98/69/CE(B) - Euro IV Directive 98/69/CE(B) - Euro IV Directive 98/69/CE(B) - Euro IV CNG G25 CNG G25 CNG G25 1,0 1,0 1,0 Range value Test Result 0,659 0,393 0,22 0,10 0,10 0,10 0,071 0,08 0,071 0,08 0,08 0,042 0,052 Pict. 6 0,029 0,012 Resume diagram of some CO HC NOx CO HC NOx CO HC NOx anti-polluting tests carried out Emission values not multiplied by the wear factor by BRC Gas Equipment
  7. 7. GUIDE TO CNG 7 5. CNG SPREAD lity, to industrial and technologic years program for natural gas deve- IN AUTOTRACTION progresses and to economic and lopment, and addressed its interest ecologic good reasons. Many to the international industry of assi- governments have already actuated stance and programming. The a precise energetic policy introdu- national oil company (NIOC - cing this kind of fuel and supporting National Iranian Oil Company) it with economic and fiscal incenti- wishes to use natural gas in all its ves. territory in order to keep a high oil On April 25th 2002, American exportation ability. Moreover, Iran Senate approved for the first time, considers natural gas as a solution 5.1. CNG IN THE WORLD with a 88 votes against 11, an to partially solve the pollution pro- energy law. This law includes incen- blem in Teheran and other cities CNG for autotraction has quickly tives about taxes on vehicles sup- increased its development all over plied with alternative fuels. CNG has also a very important the world thanks to its big availabi- Iran started an ambitious 10- role in domestic, industrial and agri- Pict. 7 Co u n tr y V eh i cl es F il li n g F i l li n g s t a t io n s F i l li n g La s t c o nv e rti ed s t a t io n s u n d er p l an t s u p d a te Vehicles to CNG co n s t r u ct i o n converted to CNG and filling stations Argentina 951.842 1.068 98 - May 2003 Brazil 550.010 570 150 - June 2003 in the world Italy 434.000 405 40 - May 2003 Pakistan 360.000 360 200 - June 2003 (Source: The GVR - India 156.659 161 - - June 2003 Luglio 2003) USA 130.000 1.300 - 3.271 May 2003 China 69.300 270 - - April 20003 Egypt 44.810 75 25 - May 2003 Venezuela 44.146 147 - - January 2003 Ukraine 41.000 130 - - June 2003 Russia 32.000 216 - 2 March 2003 Taiwan 24.000 12 - - February 2003 Canada 20.505 222 - 3.208 August 2001 Japan 16.561 224 - 606 May 2002 Bolivia 15.000 30 6 46 April 2003 Germany 15.000 330 500 450 April 2003 Bangladesh 14.015 15 25 - June 2003 New Zealand 12.000 109 - - March 2000 Colombia 9.126 32 12 - April 2003 Belarus 5.500 24 - - December 2001 France 4.550 105 - 100 October 2000 Trinidad & Tobago 4.000 12 4 - March 2003 Malesia 3.700 18 - - October 2000 Sweden 3.300 32 3 - January 2003 Chile 3.000 12 5 - April 2003 Indonesia 3.000 12 - - September 1996 Korea 2.612 33 7 - January 2003 Australia 2.104 127 - 55 July 2001 Mexico 2.000 4 2 - April 2003 Thailand 1.182 5 - - January 2003 Iran 1.000 3 500 - April 2003 Moldavia 800 87 - - December 2001 Spain 403 21 - 12 February 2003 Great Britain 400 40 20 40 April 2003 Turkey 400 2 - - April 2003 Belgium 300 5 - 60 February 2000 Czech Republic 300 16 - - June 2003 Holland 300 11 4 40 March 2003 Switzerland 279 27 10 50 February 2003 Austria 250 44 - 25 February 2003 Portugal 243 5 2 - May 2002 Poland 98 21 - 17 April 2003 Norway 88 4 - - April 2003 EIRE 81 2 - 6 September 2000 Finland 75 3 - 2 June 2003 Cuba 45 1 - - February 2001 Iceland 42 1 - - June 2003 Nigeria 28 2 - - May 1998 Luxemburg 25 5 - - June 1999 South Africa 22 1 - 4 January 2000 Uruguay 20 - - - December 2001 Denmark 5 1 - 3 February 2000 Singapore 4 1 - - February 2003 Total 2.931.680 6.388 1.613 7.997
  8. 8. 8 GUIDE TO CNG cultural field. Pict. 8 Y ea r B i o- fu e l s Me th an e H y d ro g e n Prospect of the 5.2. CNG IN EUROPE % % % European Commission European Commission propo- 2005 2 - - (Source: Metano & Motori - October sed a directive for promoting use of 2010 6 2 - 2002) alternative fuels (bio-fuels, CNG, 2015 7 5 2 hydrogen) for transpor tation, to comply with the energetic security 2020 8 10 5 schedule planned in November 2000 with perspectives up to 2020. builders introduced in their offer Table in picture 8 shows hypothesis vehicles with current CNG and about possible use of the alternati- petrol supply (bi-fuel) or CNG sup- ve fuels mentioned above in place ply. of oil products (petrol and diesel oil). CNG has a big impor tance from this point of view. Some of the most impor tant European cities (Helsinki, Athens, Porto, etc.) adopted fleet of buses supplied with CNG to reduce costs and urban pollution. All European Governments are studying, or have already passed, laws and development plans for CNG in autotraction. 5.3. CNG IN ITALY Italy, after Argentina and Brazil, is the third country in the world for number of CNG vehicles and the first in Europe for number of service stations, but their increase in Germany and USA undermines this record (see table in pict. 7). CNG Italian sales network has more than 400 filling stations already operating, and many others under construction, where refuelling can be realized in less than 3 minu- tes. By now, there are still a few CNG filling stations along the motorways, but soon they’ll increa- se, thanks to the further opening of 15 stations. In Italy, more than 400.000 vehicles are supplied with natural gas, and this number inclu- des urban buses, public or private company fleet, taxi cabs and light and heavy means for goods tran- sportation. Following new trends, many car
  9. 9. GUIDE TO CNG 9 CNG EQUIPMENT ried out by installer’s workshop, if tings, required. CNG system doesn’t pro- - CNG Valve, voke vehicle substantial changes, but - CNG Manometer. it just needs some components to be added: we’ll describe them in the fol- 6.2.1. REFUELLING COUPLING lowing chapters. Ever y CNG system needs a 6.2. COMPONENTS refuelling coupling to refuel the COMMON TO ALL CNG cylinders. EQUIPMENT There are many kinds of refuel- 6.1 LAWS IN FORCE ling couplings, according to the dif- Most of components you need ferent countries, but work and CNG equipment installation is to convert a petrol vehicle to CNG, safety characteristics are the same widely diffused all over the world. normally the ones placed in the for each BRC model. There are two There are many laws regulating this rear side, are common to every kind different versions of refuelling cou- activity, some with national influence, of vehicle, namely to the carburet- plings: other with a bigger one. Among the tor, the injection and the injection with female fitting for installa- most impor tant laws, we find the with catalyst ones. tions combined with VMA3 CNG regulation ECE ONU R110 part I, We’re going to describe now valve inside the engine compart- establishing rules for CNG compo- functions and main features of the ment (pict. 9); nents homologation, and part II esta- following components: with female fitting for wall leadth- blishing rules about their installation. rough installations on the car Norms ISO 15500 establish characte- - Refuelling coupling, bodywork (pict. 10). ristics for components test; these - Cylinders Valves, For a wall leadthrough installa- norms are applied where R110 is not - CNG Cylinders, tion, realize a hole where you wish accepted. Norms ISO 15501 and ISO - High-pressure pipes and fit- to install the coupling on the 15502 instead, concer n CNG systems installation on vehicles, and tests to be carried out on them. Pict. 9 Today in Italy the R110 regulation “IMA5” refuelling is in force for OEM installations (first coupling: installation on assembly), and Protocol n° 4043- “VMA3E WP” MOT2/C of 11.21.2002 is in force for “IMA5” refuelling solenoid valve coupling “after market” installations. Italy adopted amendments of European Regulation N. 110, where indications about approval of supply devices for vehicles converted to CNG are defined. Previous national “VMA3E WP” laws, therefore, became “obsolete” as , solenoid valve articles 341 - 351 of Regulation for accomplishment of Highway Code, and various circulars previously emit- Pict. 10 ted by the Ministry of Transport. 6 8 “IMA5/P” refuelling After introducing the regulation coupling: 4 7 wall leadthrough R110, with prot. n. 4043-MOT2/C of installation 5 11.21.2002, norms for installing these 2 components on vehicles have been 3 defined. Provincial Offices of Land Transport Department verify the com- 2 1 pliance of components installation with laws and every system tightness LEGEND by submitting them to a hydraulic 1 = “IMA5/P” coupling; 2 = washers; 3 = cap; 4 = vehicle; pressure of 300 bar. Test can be car- 5 = nut; 6 = locking ring; 7 = fitting; 8 = gas pipe.
  10. 10. 10 GUIDE TO CNG bodywork, and fix it with the suita- Pict. 11 ble nut. Then, screw steel pipe to “IMA6/P” refuelling the coupling with fitting and locking coupling: example of ring (pict. 11). installation All couplings are made up of a into the petrol filler main body, where refuelling gun has to be hooked. Inside the cou- pling, there’s a non-return valve stopping the gas flow after refuel- ling. During the refuelling, pressure of the gas coming in pushes shutter down; then, once gas flow stopped, it comes back to its previous posi- tion thanks to a spring. A plastic closing cap, present or not in accor- Pict. 12 dance with the refuelling coupling 1 9 LEGEND “VB A1” position, protects it from possible 1 = cylinder; cylinder valve: 2 = valve body; 3 section view, instal- foreign bodies. 3 = clamp; led 4 = gasket Refuelling point assembly doe- sleeve; on cylinder 8 5 = excess flow sn’t influence the working principle device; of CNG system in which it’s instal- 7 6 = vent hose bursting disk and led (it doesn’t need adjustments); thermic fuse; however, it has to respect installa- 7 = ventilation breather; 2 8 = closing pivot; tion norms in force in the country 4 5 6 9 = handle. where it’s installed. 6.2.2. “VB A1” CYLINDER VALVE “VB A1” cylinder valve was plan- Pict. 13 ned and produced by BRC to com- “VB A1” bined cylinder valve traditional func- cylinder valve: exploded view tions with safety functions interna- tionally required for this kind of device. 1 BRC, on the basis of its expe- rience in national and foreign 2 markets, realizes many versions of “VB A1” cylinder valve, according to LEGEND 1 = “VB A1 valve”; the laws in force in each country. 2 = Gasket sleeve; Especially, the following func- 3 3 = Clamp tions stay the same in each model: - Cylinder refuelling, fuse. tion to the steel pipe in case of wall - Cylinder supply, leadthrough couplings. With cou- - Cylinder insulation by means “VB A1” cylinder valve is made plings not needing a wall leadthrou- of a manual tap, up of a main body with a threaded gh installation (applied on the “VM - Ventilation for gas-tight hou- fitting for connecting it to the cylin- A3” CNG valve), we apply a blank- sing. der, and two threaded fittings for off plug on the last valve fitting not connecting it to the high-pressure used. The following safety devices can pipes. Normally, we use one of The CNG flow coming out from be added to the standard model: these fittings for the connection to the cylinder is intercepted by the - Excess flow valve, the refuelling point and to the engi- conical shutter realized by the pivot. - Safety device for overpressure ne supply, and the other one for the If shutter is open, CNG flows with bursting disk, connection to other cylinders. Last towards the engine through the hole - Safety device with thermic valve fitting is used for the connec- perpendicular to the section plane.
  11. 11. GUIDE TO CNG 11 Through the same passages, but in However, you can close the gas ded for the European Regulation nr. the opposite way, CNG flows during outlet thanks to the manual tap 110 applied in Italy with Prot. 4043- the refuelling. situated on the valve in case of MOT2/C. By turning clockwise the handle, emergency or maintenance. shutter goes down and valve clo- 6.2.4.2. General instructions ses. 6.2.4. CNG CYLINDERS Cylinders must be installed inside the vehicle template, inclu- 6.2.2.1. Excess flow valve CNG cylinders are the biggest ded the vehicle rear side, and so Excess flow valve reduces as additional element of the equipment that they result protected enough much as possible CNG leakages and they are normally installed insi- from crashes. Near the cylinders, from the cylinder in case of too high de the luggage compartment, and shar p edges must be absent. flows due to anomalies, such as sometimes under the bodywork, Cylinders position in the template disconnection or breaking of the under the flatcar, or on the sunroof. is not submitted to special orienta- outlet pipe. Of course, cylinders have to tion bonds. We can install on the comply with prescriptions of same vehicle one or more cylin- 6.2.2.2. Bursting disk European Regulation n. 110, or with ders equipped with one or more Bursting disk is a security device any laws in force in the destination refuelling lines. For fixing cylin- for overpressures. country. According to needs and ders to the vehicle, we have to It has the task to intervene if spaces, one or more cylinders can use measured anchors resisting pressure inside the cylinder over- be installed on the vehicle. to stresses due to a vehicle acce- passes the setting value, and to We can easily say that cylinders lerations with full tank. discharge all the cylinder contents. are one of the safest components Please make reference to the of the whole vehicle. table in picture 15 to choose all 6.2.2.3. Thermic fuse Real experience, in fact, shows fixing clamps and nuts. Thermic fuse is a safety device that, even in case of serious hard Cylinders position has to not intervening in case of over-tempera- crashes, CNG cylinders are one of provoke friction while vehicle is tures (in case of fire, for instance); it the few parts of the vehicle remai- running; so, it can be useful to allows evacuating the cylinder con- ning complete. Even in case of insert some anti-sparkling and not tents, avoiding so its explosion. pileup collision, cylinders don’t hygroscopic material among cylin- change its shape; so, it’s completely ders, and between them and the We can find the described three untrue the diffused preconception fixing system (pict. 16). available versions individually or about cylinders danger. Cylinder valve/s must be pla- together, according to the laws in ced in a position easy to reach. force in the destination country. 6.2.4.1. Installation Petrol tank and CNG cylinders Main body can have the shape Before going on with the cylin- don’t have to touch, but rather be you can see in picture 12, or the ders fixing, it’s necessary to install well separated. one shown in picture 13. on them respective cylinder valves This latter has a square ridge described in the previous para- 6.2.4.3. Installations under allowing tight the cylinder valve on graph. the bodywork or under the cylinder itself, without needing To describe CNG cylinders the flatcar any special wrenches. installation, we’ll follow what provi- Cylinders must be suitably 6.2.3. “VB S1” (E13 110R) Pict. 14 CYLINDER VALVE “VB S1” cylinder valve “VB S1” valve (pict. 14) is the evolution of the “VB A1” one. It has all the characteristics of this latter, but it adds a shut-off solenoid valve directly inserted on its body. BRC ECUs suitably pilot the solenoid valve, stopping so the gas flow towards the engine in case of accident or accidental shutdown.
  12. 12. 12 GUIDE TO CNG insulated from silencers and exhaust gas ducts by means of a C y l i n de r/ s Rings, plate s or n om i n a l t wo th r ee s u pp or t s f or N ut s metal sheet, or of material with c ap aci ty c lam p s c lam p s fi x i ng t o th e d iam e ter the same characteristics and at (C) c a r b od y least 1 mm thick. Minimum distance bet ween cylinders and ground cannot be litres (mm) (mm) (mm) shor ter than the one bet ween vehicle and ground (in the table, C ≤ 100 30 x 2,5 30 x 1,5 30 x 6 M12 you can find minimum values 100 ≤ C ≤ 150 50 x 2,5 50 x 2 50 x 6 M14 fixed by the Italian Prot. 4043 Pict. 15 - Resume table of minimum dimensions and characteristics required for clamps, nuts MOT2/C). and supports for fixing cylinders, in accordance with the Prot. 4043-MOT2/C. 6.2.4.4. Installations on the Pict. 16 sunroof Steel pipe VBS1 valve Cylinders must be protected from Installation of CNG cylinder sunbeams by suitable containers inside the luggage with pierced walls avoiding the gas compartment: Breather insulation and accumulation. This shield has to ventilation cover 180° at least. Placing cylin- Cylinder ders to the bodywork or on the sun- roof, it’s necessary to follow the mass placing and subdivision crite- ria indicated in the vehicle use and maintenance booklet (table CUNA Vent hoses NC001-51). closed spaces, Prot. 4043-MOT2/C with a pressure of roughly 20 bar 6.2.4.5. Installations inside the orders to create t wo fur ther air inside the cylinders. rear luggage compartment with intakes, with a inside diameter not ventilation system lower than 25 mm. They must be 6.2.5. HIGH-PRESSURE PIPES If cylinders have been placed done on one side of the compart- AND FITTINGS inside the rear luggage compart- ment, as high as possible. It’s ment, it’s necessary to realize a sui- necessary to protect the two air With the words “high-pressure table ventilation assuring that, in intakes in order to avoid that lugga- pipes” we mean pipes connecting , case of leakages or other anoma- ge compar tment could obstruct valves with possible refuelling cou- lies, CNG could flow towards the them, and being careful with always plings, cylinder valves among them- vehicle outside, avoiding so its keep a good air circulation. selves, cylinder valve to the shut-off accumulation in dangerous and not valve of engine compartment, and suitable areas. This ventilation can 6.2.4.6. Assembly general shut-off valve to the reducer. be realized as shown in picture 16 warnings This pipe, normally made of and 17, by making two holes con- Before realizing holes or breaks unsoldered steel, is suitable for a necting the luggage compartment in the bodywork, be careful with no working pressure of 330 bar, and it with the outside, and inserting here damage pipes, cables, tanks and can be bended with suitable tools if breathers and vent hoses. The pas- other elements. Before effecting the needed. sing hole on the valves body assu- tanks full refuelling, check the pre- Unsoldered steel pipe used in res ventilation on each valve. Prot. sence of leakages with soap water the high-pressure part is not sub- 4043 MOT2/C establishes the mitted to approval but, however, it breather inside diameter minimum V eh ic le M i n i m um has to comply with requirements of measure at 30 mm. Breathers and I n t e rn a t i o na l di s ta n c e European Regulation n. 110. c a t e g or y fr o m gr o un d vent hoses are normally used for Pipe is connected to the different (m m ) steel high-pressure pipes passage devices (cylinder valves, refuelling (pictures 16 and 17). couplings, shut-off valve, reducer) If, eventually, installation inside M2, M3, N2, N3 200 by means of suitable pipe-fittings the luggage compartment creates M1, N1, L4, L5 155 (pict. 19, detail of steel pipe fitting).
  13. 13. GUIDE TO CNG 13 For fixing pipe to the car Pict. 17 bodywork is better to respect pre- Installation of scriptions in force in the different CNG cylinder inside the luggage Countries, considering that it must compartment: be fixed at the bottom of the vehi- ventilation breathers cle, far away from the exhaust pipe assembly and from vehicle strengthening points, at a regular distance by using suitable clamps with self-tap- ping screws. Connections, where subjected to vibrations, must be Steel pipes made by coil or elastic spirals (pic. 20). 6.2.6. “VM A3” CNG VALVE Pict. 18 “VM A3” CNG valve is a device Example of planned and produced by BRC to installation of CNG cylinder intercept CNG on the high-pressure inside the luggage line, normally between cylinders compartment (Citroën Xsara and reducer. Generally, “VM A3” is Picasso) installed in the engine compart- ment, together with a quick cou- pling for CNG refuelling. BRC, on the basis of its expe- rience in national and foreign markets, realizes two versions of “VM A3”: - “VM A3/R” CNG valve with manual tap. Pict. 19 - “VM A3/E” CNG electro-assi- 4 High-pressure sted valve. pipe 6.2.6.1. “VM A3/R” CNG valve with tap 6 “VM A3/R” (pict. 21) is made up 2 1 of a brass pressed main body (1). 5 4 On the body itself, there are the two 3 opposite clutches for connection to the high-pressure pipes, cylinders LEGEND 1 = “VBS1” cylinder valve; 2 = gasket sleeve; 3 = clamp; side and reducer side, and the clut- 4 = gas pipe; 5 = fitting; 6 = locking ring. ches for manual tap on one side and for refuelling coupling on the other side. Pict. 20 As you can see in picture 21, High-pressure “VM A3/R” allows refuelling the pipe: elastic spiral cylinders, if combined with the refuelling coupling, and insulating the part of the system downstream the cylinders (refuelling coupling and pressure reducer) closing the manual tap. The handle allows moving the shutter.
  14. 14. 14 GUIDE TO CNG 6.2.6.2. “VM A3/E” CNG valve Pict. 21 with solenoid valve “VM A3/R” As you can see in pictures 21 CNG valve: exploded view and 22, “VM A3/E” keeps the same standard functions of the manual tap version, being obtained from the same brass pressed, the same shape too. The only difference is the presence of a solenoid valve in place of the manual tap. This diffe- rence allows insulating the part of the system downstream the cylin- ders (refuelling coupling and/or pressure reducer according to the version) during every vehicle shut- down and ever y changeover to petrol, if suitably piloted by the ECUs. LEGEND 1 = “VM A3” valve body; 2 = OR 2062; 3 = nut for pivot; 4 = pivot slide bush; 5 = SR 007 anti-extrusion ring; 6 = OR 2015; 7 = tap group pivot; 8 = 7/32” ball; 9 = M16x0,75 fitting; 10 = valve handle; 11 = csk allen screw M4x10; 12 = cap; 20 = M12x1 fitting; 21 = locking ring; 22 = bracket; 23 1/2” gas nut; 24 = “IMA5” refuelling coupling. Pict. 22 “VM A3/E” WP CNG valve: combined with “IMA6” coupling
  15. 15. GUIDE TO CNG 15 6.2.7. CNG MANOMETER Pict. 23 CNG manometer: Being CNG stocked in tanks at exploded view of assembly on its gaseous state, fuel level is calcu- gas fitting at lated in accordance with pressure “Genius.M” reducer inlet coming out from the tank. This task is carried out by a needle manometer, placed on the reducer inlet fitting (pictures 23 and 24). It gives indication about tank outlet pressure, and so about auto- nomy remained. Visual data given by the mano- meter can be sent to the BRC ECUs by joining the suitable con- nector. Fuel level, so, will be displayed into the passenger compartment too, on the ECU LED bar of the system installed. Pict. 24 CNG manometer: example of assembly on Tecno.M reducer
  16. 16. 16 GUIDE TO CNG As we already said in § 6.2, task to stop original fuel flow during mechanical and electric compo- the gas mode. nents situated downstream the manometer change according to 6.3.1. PETROL SOLENOID VALVE the vehicle original supply, which AND PETROL NON-RETURN VALVE can be a carburettor, an injection, a catalyzed injection, or a superchar- As already said in the previous ged supply. paragraph, petrol solenoid valve is Moreover, each kind of supply a device allowing the petrol flow needs some special precautions to interruption when car works with give a good vehicle working. CNG supply. It’s made up of a shutter moved 6.3. THE CARBURETTOR by a magnetic coil and by two fit- Pict. 26 - Petrol solenoid valve VEHICLE tings, an inlet and an outlet ones. Solenoid valve has also an fixed with the coil upright, far away CNG conversion and compo- emergency device allowing the from “dangerous” parts of engine nents kind and position of a carbu- manual reset of petrol passage in compartment. Anyway, its position rettor vehicle are substantially the case of problems with the wiring might allow reaching the reset devi- same of the ones indicated in pictu- system. ce. re 25. CNG, coming from the tank, Petrol solenoid valve (pict. 26) is Moreover, it’s important to verify by means of a high-pressure pipe closed at rest and it opens when if on carburettor there’s a by-pass and intercepted by “VMA3” reaches , current passes through it. It must be pipe for petrol coming back to the the pneumatic or electro-assisted installed in the engine compartment tank. In this case, insert on this pipe reducer-vaporizer. Here, thanks to between petrol pump and carburet- a petrol non-return valve. For the water coming from the engine tor. It shows an arrow indicating the obtaining a correct installation of coolant equipment, it gets warm. right petrol running direction in the two devices, we suggest to fol- On carburettor vehicles, a spe- order to simplify its assembly. low instructions given by picture 27. cial “petrol solenoid valve” has the Petrol solenoid valve must be Changeover ECU Coil FUSE Reducer Petrol solenoid valve Mixer Adjusting screw “VMA3/E” CNG valve Pict. 25 Components Engine “VB A1” layout of valve CNG equipment CNG cylinder on carburettor vehicles
  17. 17. GUIDE TO CNG 17 6.3.2. TRADITIONAL REDUCER Gaseous CNG, after overcoming the “VMA3” CNG valve arrives to the reducer that can be considered the real equipment “lung” not only , Pump Original from a technical point of view, By-pass Petrol SV Tank Carburettor carrying out a primary role. A) DON’T INSERT THE PETROL NON-RETURN VALVE It adjusts pressure to a value near the atmospheric one, making fuel available for the engine intake. Reducer lets pressure down through three reduction stages: - first stage lets the pressure coming from the tank down from 220-250 bar to 5-6 bar. Pump - second stage brings pressure Petrol SV Tank Carburettor coming from the first one to 1,5 - 2 bar. B) DON’T INSERT THE PETROL NON-RETURN VALVE - third stage reduces pressure to a value near the atmospheric one. In order to avoid its freezing for Petrol non-return valve the abrupt gas expansion, reducer is warmed using the engine coolant water, suitably derived. Reducer must be installed verti- Pump Petrol SV Tank cally, with diaphragms parallel to Carburettor the vehicle running direction. It C) INSERT THE PETROL NON-RETURN VALVE must be installed in a place easy to reach in order to carrying out adju- stment and maintenance. The hole PICT. 27 - Installation of Petrol Solenoid valve and Petrol non-return valve on carburettor vehicles. on the cap of reducer second stage must stay free, so that diaphragm Pict. 28 not touching the gas is always at “BRC MP” pneumatic the environmental pressure. reducer Special attention must be paid to the reducer heating system. -Cut the water pipes going to the heating system of passenger compartment and connect them with some “T” fit- tings to the reducer pipe-holders. Connect water delivery to the redu- cer “IN” inlet fitting, and water back- flow to the reducer “OUT” outlet (picture 29). This is a very important connec- tion because engine coolant liquid brings inside the reducer heat necessary to warm CNG after the abrupt pressure reduction. device, while in case of engine tly adjust the reducer, however, it’s In the Pneumatic reducer, LPG accidental or voluntary shutdown, necessary to follow instruction you necessary to start the vehicle is vacuum lack impedes LPG rea- can find in every pack. supplied by an electro-pneumatic ching the engine. In order to correc- Moreover, for the vehicle correct
  18. 18. 18 GUIDE TO CNG working, we want to remember that Pict. 29 it’s necessary to block thermostat CNG reducer: blade, in order to close hot air water circuit intake, orienting the frontal intake towards lower or rear side of the OUT vehicle. IN 6.3.3. MIXER CNG reducer This device, situated down- Engine stream the reducer, realizes the right air-fuel mixture. Mixer for carburettor vehicles can be realized by using the carbu- rettor Venturi or by creating on it an independent Venturi. To the first family belong: - dual-purpose system (nozzle or clutch), consisting in a pipe Pict. 30 inserted by drilling carburettor, CNG reducer: - fork system, consisting in one BRC vacuum for or more pipes inserted into the car- pneumatic burettor without drill it, reducers Intake - separate Venturi system. manifold To the second family belong: CNG - "classic" mixers, installed reducer upstream the Venturi and whose position changes in accordance with vehicle, Engine - plate mixers, installed above the throttle body, under the air filter box. Exhaust manifold 6.3.3.1. Dual-purpose system This solution (pict. 31), can give the best results if well done, but it cannot be realized on every kind of carburettor and it can seriously Pict. 31 damage carburettor if not well done. Dual purpose Moreover, it requires much time and mixer (with clutch) experience to be realized. The choice of drilling position is conditioned by the necessity to place connection as in picture 32. Gas inlet must be made so that the clutch higher generatrix remains a little under the narrow section of Venturi pipe (2-3 mm); generally, this position coincides with the car- burettor separate Venturi extremity. Once the right position found, pay the best attention with avoiding interception of petrol while drilling.
  19. 19. GUIDE TO CNG 19 Clutch, blunted at 45°, will have Pict. 32 to be screwed into the carburettor Dual purpose so that the clutch centre overpas- mixer ses carburettor axis for some milli- (with clutch): installation metres. Then, clutch tight must be assured by using chemical products or a nut. Vacuum Gas inlet 6.3.3.2. Fork system Pict. 33 For sure, this solution (pict. 33) Fork mixer is easier than the previous one. The only precaution to adopt is slightly trim the starter throttle body to allow its working. In this case too, you have to pay attention with leaving a fork extre- mity long enough to reach 2-3 mm under the narrow section of Venturi pipe (if too long, you have to shor- ten it). Gas flow pipes don’t have to pass through the air filtering ele- ment, but only through the air filter box (normally in plastic) (pict. 34). Fork mixer Pict. 34 Fork mixer: installation Gas inlet Vacuum
  20. 20. 20 GUIDE TO CNG 6.3.3.3. Separate Venturi system Pict. 35 Separate Venturi mixer (pict. 35) fol- Separate Venturi lows substantially the same princi- mixer ple of fork system. Generally it’s less economic, as it’s realized to satisfy special requirements of a specific vehicle. This system allows sometimes avoiding the starters throttle bodies trimming. 6.3.3.4. “Classic” mixers They represent another good solu- Pict. 36 tion, because they allow a very “Classic” quick assembly. Normally, they’re clutch mixer installed on the air pipe coupling. Classic mixers can be both of clut- ch (pict. 36) and corollary (pict. 37) type, in accordance with the vehicle characteristics. Pict. 37 “Classic” corollary mixer Pict. 38 6.3.3.5. Plate mixers They’re installed on the throttle Plate mixer body. In most of cases, it’s neces- sary to lift up the air filter box and fix mixer on the throttle body with screws you’ll find in the pack. These mixers, thanks to its little overall dimension, allow a good working and a very quick assembly (pict. 38).
  21. 21. GUIDE TO CNG 21 6.3.4. WIRING SYSTEM ON CARBURETTOR VEHICLE Green Orange Possible reserve On this kind of vehicle, it’s possi- sensor Grey Brown +12V ble to install both a changeover under key switch with manual “star ter” White (pict.39) and an ECU with automa- Ground tic “starter” (pict. 40). In the first case, during the star- ting up, it’s necessary to manually Petrol solenoid activate a changeover switch button valve that, thanks to its connection to the “BRC MP” CNG reducer solenoid valve situated on the pneumatic reducer, allows the pas- sage of a defined gas quantity to start up the vehicle. “Safety” func- tion is obtained thanks to the vacuum realized on the intake Ground manifold (pict. 30). “VMA3/E” CNG valve T100 In the second case, instead, an GAS/PETROL electronic circuit manages the pro- CHANGEOVER SWITCH cedure and an electronic stage of rpm reading allows the Safety func- tion. Connections, anyway, are extre- mely easy, and following instruc- Fig. 39 - General connection diagram of “T100” changeover switch with manual starter, with tions contained in the packs is “BRC MP” pneumatic reducer. enough to correctly install and adju- st the device. Green Brown +12V 7,5A under key + - Grey Black Ground Coil White Ground Petrol solenoid Ground valve “BRC ME” CNG reducer Possible White/Black reserve or resistive sensor Ground “VMA3/E” CNG valve Possible cable for connection to the Hall level sensors Bristol Pict. 40 General connection diagram of “Bristol” ECU with automatic starter, with electroassisted reducer “BRC ME”

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