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[JamesV6CDX]

As Mark says, it's very simple. There is nothing to it.

I got it apart, absolutely full of brown goo. So I give it all a damn good clean out, make sure everything is fitting right, and reassemble it, re-sealing with a smear of sealent on the surfaces.

I fitted it to the car, in anticipation.. and......


B*gger.

It won't run on gas at all now. The soleniod flicks over, the gas lights come on, and then it just dies.

Any ideas? Have I killed the Vaporisor?

[Kevin Wood]

Could it be that someone has tweaked up the adjustments to make it run while fubar and they're now wrong?

.. but I know nothing about setting them up.

Kevin

[JamesV6CDX]

Could it be that someone has tweaked up the adjustments to make it run while fubar and they're now wrong?

.. but I know nothing about setting them up.

Kevin

Neither do I....

I recon, strip the car, for enough to buy an SGI front end....

But then, would that require the same level of setting up?

[Martin_1962]

Did you dislodge any springs?

Do you still have Bernards phone number?

[Kevin Wood]

I'm sure it can't be that hard to get it running, but watch it doesn't go lean and backfire, as that can be nasty with a mixer.

SGI would likely have some kind of fuel map to fill in - and that I can do

Or, at least, I have, with Petrol.

I would have thought they could self-learn most of it from the Lambda sensor outputs, TBH, but I have no practical experience of them. Martin to the forum, please!

Kevin

[JamesV6CDX]

Just thinking time may be better spent recouping some costs from a car, and getting the tank etc into mine... then get an SGI front end for £500

[Kevin Wood]

True. There's not a lot to be achieved by getting it going now if that's the final aim.

Before you start putting bits into the new car it'd be worth lining up someone who'd be prepared to certify it and reading up on all the rules and regs, and maybe discussing your intentions with them because there are bound to be loads of do's and don'ts.

Kevin

[JamesV6CDX]

True. There's not a lot to be achieved by getting it going now if that's the final aim.

Before you start putting bits into the new car it'd be worth lining up someone who'd be prepared to certify it and reading up on all the rules and regs, and maybe discussing your intentions with them because there are bound to be loads of do's and don'ts.

Kevin

I think Martin knows someone who can certify it, in Church Lench?

I will certainly read the LPGA CoP...

[Martin_1962]

Re: [lp-gas] Servicing Evaporators


Replace the two diaphragms. Watch out that the little connecting pin
moves freely as you reassemble.

Hugh

[Martin_1962]

                          INTRODUCTION OBJECTIVE AND SCOPE
 
  INTRODUCTION
 
LPG has been used as an internal combustion engine fuel for a great many years.
This revision of the 1992 edition recognises the advances in engine design and the
improvements in engine management systems. It also now includes guidance on fuel systems for heavy duty engines for buses and coaches and passenger service vehicles which usually involve conversions from diesel fuel or the use of such engines specifically designed for LPG operation.
 LPG engine fuel systems are now available for all generations of spark ignition management systems. These are broadly defined as follows:-

 1st generation             Carburettor air-gas mixing systems.

 2nd generation           Carburettor systems with micro processor control  derived

  from engine speed, manifold pressure and lambda sensor for optimising 3-way exhaust catalyst operation.

 3rd generation              Multi-point liquid or vapour injection systems, but with  non-adjustable self learning feedback controls.

  There are many variations of property systems available, but the principles are illustrated in Appendix 4.

 Most LPG conversions from petrol are bi-fuel systems retaining the petrol fuel system as
an alternative.

 Diesel conversions are dedicated LPG systems since diesel compression ratios are too high for LPG and require piston or cylinder head modification.

 There are heavy duty engines available designed specifically for LPG operation.

  OBJECTIVE.
 To set minimum standards for the safe installation and use of LPG as a road vehicle engine fuel.

 Scope
The Code includes the design and installation of the fixed LPG fuel tank or tanks, and the fuel feed system comprising fittings, pipework, connections and controls for internal combustion engines of road vehicles including bi-fuel installations (for LPG or petrol operation), or conversions from diesel, or specifically designed engines for LPG operation.

 Buses, including Public Service Vehicles (PSVs) are covered in Section 6 to draw attention to the special requirements for this important sector of the road vehicle industry in view of the interest in introducing LPG as a means of reducing urban pollution.

 Both vapour feed and liquid feed systems are included to cover all four generations of engine design, including injection. Detailed design or modification of the engine and its management system, and the electronic controls for stoichiometric or lean-burn
operation are all state of the art developments subject to continuous development by engine manufacturers and conversion specialists, and are not part of this Code.

 The Code excludes fuel systems for:-  Dual fuel engines i.e.LPG-Diesel
 Fork-lift trucks  Stationary engines i.e. non-transport

 DEFINITIONS

 For the purpose of this Code the following definitions shall apply:-

 Competent Person:   A person with knowledge, training and ability to carry out their work safely and with the necessary proficiency to ensure the subsequent safe operation of the vehicle.
 Component:  Any equipment through which LPG or other fuel flows and is added as part of the vehicle conversion.

 Gas Container :  The term used in the “ Construction and Use”Regulations meaning a fuel tank which is a pressure vessel for the storage of LPG to be used as an automotive engine fuel.

 Contents Gauge:  A guage which gives visual indication of the liquid contents of the fuel tank.

 Bi-Fuel:  Where two alternative fuels are provided.

 Dual-Fuel:  Where two different fuels are fed to the engine simultaneously:usually a
gaseous fuel addition to a diesel engine.

 Bus:  A motor vehicle which is constructed or adapted to carry more than eight seated
passengers in addition to the driver (Road Vehicles Construction and Use Regulations).

 Passenger Service Vehicle(PSV).  A bus used for carrying passengers for hire or reward, or other vehicle, except a taxi used for carrying passengers for hire or reward at separate
fares in the course of business (Public Passenger Vehicle Act 1981).

 
Mini-Bus:  A bus designed to carry seated more than eight passengers but not more than
sixteen excluding the vehicle driver.

 Fixed Maximum Liquid Level Indicator:  A gauge which indicates the maximum permitted liquid level in the fuel tank. It comprises a tube arranged with its open end located at themaximum permitted liquid level, so that gaseous discharge changes to a visible liquid discharge as the liquid surface reaches  the level during filling.

 Hydrostatic Relief Valve:  A valve whose purpose is to relieve and prevent over pressure due to thermal expansion in any supply pipeline carrying LPG in the liquid state.

 Stop Fill Valve:  A double check level device, which prevents the over filling of a fuel tank beyond a pre-determined liquid level. (usually 80%).

 Lock-off Valve:  A term used to describe a shut-off valve in the fuel feed line which will
automatically shut-off the fuel feed to the engine under specified conditions relating to
 vehicle operation and safety.

 Lambda (^)   The ratio of air supplied to an engine to the stoichiometric air required.
 At stoichiometric ^=1: lean burn^> 1.

[Martin_1962]

Multiple Valve.  A manifold block which requires only a single nozzle opening in the fuel tank which incorporates all or some of the following fittings: 80% stop-fill valve, level indicator, pressure release valve, service valve with excess-flow valve, and fuel pump.
 
Gas Tight Housing:  A cover mounted over the fuel tank fittings to protect them and to prevent gas leakage entering a vehicle, and to vent to the open air.

 Non-Return Valve:  A device to permit flow in one direction and prevent the flow in the
 opposite direction.

 Check Valve (device):  Another term for a non-return valve.

 Fill Connector:  The self-sealing fitting at the fuel tank or at the terminal of the fill pipe extension designed to accept the self-sealing coupling of the refuelling facility.

 Design Pressure:  In this Code, design pressure is the pressure for design purposes in BS5054 part 2.
 Care is necessary in using other pressure vessel standards as design is sometimes based on  the test pressure which may not be the same.

  LPG FUEL TANK OR TANKS

 Design:-
 Fuel tanks shall be designed and constructed in accordance with BS5045 Part 2 or other
equivalent recognised Pressure Valve Standard and a Test Certificate issued accordingly.


 Fuel Tanks shall have a design pressure of not less than 26 per gauge and preferably be
constructed of steel.  Other materials are not precluded where equivalent standards of
physical, thermal and chemical integrity have been demonstrated.

  Marking:_
 Each fuel tank shall be conspicuously and permanently marked with its design/test pressure and other data required by the pressure vessel standard.

 The information should include at least the following:-  

 The specification or code to which the fuel tank is manufactured.

The manufacturers name or identification mark.

The fuel tank serial number.

The minimum designed water capacity in litres.

The design/test pressure in bar gauge.

The year and month of manufacture.

The date of the hydraulic test and identification mark of the testing authority and space
 allowed for subsequent re-tests.

 These marks should not be less than 6mm in height.

 Tanks must be clearly and permanently marked to indicate the correct orientation to ensure the correct operation of the valves and contents gauge.

  Location of the Fuel Tank(s):-
 Fuel tanks shall be located in a place and in a manner as to minimise the possibility of
collision to the fuel tank and its fittings. Fuel tanks located toward the rear of  a
vehicle when protected by substantial bumpers or structure from the rear or side impacts,
 shall be  deemed to comply with this requirement.

 The vehicle manufacturer should if possible, be consulted to ascertain if there is a
recommended position for the fuel tank in or on the vehicle.

 Fuel tanks within a vehicle should be located in a sealed compartment  or should have their valves, fittings and extensions to the outside enclosed in a gas-tight housing attached to the tank. This housing shall be vapour tight to the interior of the vehicle, but vented from its lowest point to the outside of the vehicle, e.g. by a vent tube. The vent tube should have a free ventilation cross-sectional area of not less than 450mm2.

 
Fuel tanks other than those for mini-buses, estate cars and those with hatch-backs, may be
located in a vehicle compartment which is effectively sealed from the remainder of the
vehicle and ventilated to the outside. The ventilation shall be by permanent openings not
 less than 2000mm2 in total area.
 The opening should be direct to the outside air from the lowest practicable position within the compartment.
 The opening should be remote from the engine exhaust system and not closer than 250mm.
The opening should be by position, or other means, be protected from blockage both from within  the compartment or without.
 
Fuel tanks, valves and fittings may be located beneath a vehicle in a suitable
protected position.
 Fuel tanks may be mounted on the rooftops of vehicles, subject to the following:-

There shall be confirmation by the vehicle manufacturer that the location will not seriously affect the stability of the vehicle. See section on buses and PSVs.

 Crash bars and/or roll-over protection shall be provided where deemed necessary for the type of vehicle and its duty.

 Tank valves, fittings and extended pipework should be housed in a gas-tight housing as
 previously described , unless a suitable protected roof compartment is provided.
The ventilation from the gas-tight housing or compartment shall take account of the heavier than air density of LPG vapour, and shall ensure no discharge can enter the interior of the vehicleFuel tank(s) mounted underneath vehicles should be situated to ensure effective ground clearance and take account of the following:-

 The fuel tank, its fittings and any pipes adjacent thereto shall be located so as to
minimise the possibility of damage due to contact with the road or obstructions on
 the road.

 The effective ground clearances recommended by the vehicle manufacturer shall be
maintained, but where these cannot be determined then either of the options below

Shall be met. This clearance shall be measured to the bottom of the fuel tank or to the lowest fitting, support or attachment of the fuel tank if this is less.

[Martin_1962]

 Fuel tanks shall be installed with as much effective road clearance as is practicable and not less than 250mm. It should take account of the minimum horizontal clearance of the vehicle.The effective ground clearance should take account of the minimum horizontal clearance of the vehicle from the front to back and of the clearances between the axles and behind the rear axles to take account of kerbs and bridges and entry to and exit from ramps. These clearances vary considerably between vehicle manufacturers and  for different types of vehicle use, but shall be determined as follows:-

 The effective road clearance  at the fuel tank when the vehicle is loaded to the point of
 maximum spring deflection.

 The effective road clearance of the vehicle at the fuel tank position when loaded to its gross vehicle weight rating, provided that under unfavourable road conditions, a fixed part of the vehicle comes into contact with the road surface before that of the fuel tank, its fittings and adjacent pipes.

. Fuel Tank Mounting.

 Means should be provided for attaching the fuel tank(s) securely to the vehicle.
This provision may take the form of fixed lugs welded to the fuel tank during manufacture or the provision of cradles, metal straps or bonds attached to the vehicle. In order to preventdistortion of the fixing area or the tank(s) breaking loose in the event iof an impact, reinforcement of sheet metal body panels etc. should be provided by suitable meansdesigned to equally distribute the weight of the tank and its contents. The fuel tank(s) mounting shall be sufficient to resist safely a deceleration of 30g.  Care should be taken to ensure that friction, rubbing and corrosion does not take place between tank and cradle by the use if necessary of suitable friction preventing material i.e. rubber, plastic etc. Fuel tank(s) should be mounted in a level position, correctly orientated as marked.
 Fuel tanks and their fittings should be protected by position, or other means, against
 physical impact and tampering The fuel tank shell, fittings and pipework should not be run outside the plan area of the vehicle viewed from above.
 Where this requirement cannot be met collision bars or other suitable protection must be
 provided.

 Multitank Installations.

 A means to prevent the flow of liquid from one tank to another must be fitted into both the filling and fuel supply lines.

 FUEL TANK FITTINGS AND CONNECTIONS
 General
 All fittings should be constructed for LPG service and suitable for operation at a pressure
not less than the working pressure of the fuel(s) concerned.
All connections and fittings should, by position or other means, be protected against physical damage weather and tampering where possible. Manual operated valves should be readily accessible.

Connections.

 All connections to fuel tanks greater than 3mm diameter for liquid and 8mm for vapour, with the exception of those for relief valves, and contents gauges, should be provided with a self closing device eg an excess flow valve, or non-return valve, to prevent the escape of product in the event of damage to the connections.

 All liquid and vapour connections to and from the furl tanks with the exception of those for relief valves, plugged openings, and those where blind connections through the fuel tank shell are not greater than 1.4mm diameter should have shut off valves located as close to the fuel tank as practicable.

 Fuel supply valves should be clearly marked with the direction of rotation to close, if
manually operated.
The position of manual shut off valves, if not visible from the outside of the vehicle,
should be indicated by a suitable notice clearly visible from outside the vehicle.

  Fittings.

 Fittings and components subject to tank pressure shall be proven suitable for contact with vapour and liquid phase LPG and designed for a pressure not less than the tank design pressure. They may be separately mounted on the fuel tank or they may be in the form of a multiple valve system incorporating some or all of the fittings in a single tank entry/exit.

 Tank Fill Valves and Fill Connector.

 The fill valve on the tanks shall incorporate a double check valve to prevent reverse flow and an automatic stop fill shut off device fitted directly to each fuel tank. The automatic stop fill shut-off device shall be designed to limit the maximum quantity of LPG to 80% of each tank capacity, and shall meet the requirements of ECE Regulation 67 or equivalent.  

 Where tanks are located inside a vehicle an extended fill line to the outside of the vehicle
 should be provided terminating with a further check-valve and refilling connection. This
should be enclosed to prevent ingress of road dirt.

 The fill connector should be located so as to be readily accessible, but should not be fitted within 250mm of the exhaust outlet, (except buses). Adequate ground clearance shall be provided and it shall be as far as practicable in a protected position.
 The fill connector shall be compatible with the mating coupling of the refuelling facilities. The need for adaptors shall be discouraged.(An international standard is desirable and it is expected that a European standard will be issued in due course).

The essential design requirements of the fill-connector and its mating coupling are:-
 There shall be no leakage to atmosphere during the filling operation.
The design operating pressure shall be not less than the fuel tank design pressure.
Automatic self sealing shall occur immediately the refuelling coupling is disconnected.
There shall be no significant LPG release from the connector as the mating coupling is
 disconnected.The seals shall provide long term resistance to liquid phase LPG to BS6505 or equivalent.

[Martin_1962]

Adequate endurance in operation shall be proven, preferably by testing, to suit the
predicted vehicle operation.The connector shall be provided with an end cap which is vented by an aperture not greater than 1.5mm diameter, which is secured to the vehicle by a chain or other means.

  Fuel Feed Valves.
 The fuel feed outlet from each tank requires:-

 A suitably sized excess flow valve mounted directly to the tank. An excess flow valve in
this context means a device which automatically and instantaneously reduces to a minimum the flow of gas through the valve when the flow rate exceeds a set value.

 An electrically controlled solenoid valve which closes on de-energising and closes
 automatically when the ignition control is in the off position and also whenever the
 engine is not running. If it is not practical for the above valve to be fitted directly
 to the tank, it shall be fitted as close as practical and a manually operated shut-off
valve shall be fitted directly to the fuel tank.

 To relieve thermal over pressure in the fuel feed pipework due to lock-up when the solenoid valve is closed, the valve for single tank installations may be designed to permit reverse flow back to the
fuel tank. If the valve does not permit this, or if a manual valve is fitted at the tank
outlet, ahydrostatic relief valve will need to be incorporated which may relieve back to the tank, where the volume of gas which is locked up exceeds 200ml.
 For inter-connected multi-tanks reverse flow solenoid valves may not be suitable unless
 other means are provided to ensure that overfilling of any tank from the others
is prevented.

   Safety Relief Valve.

 Each fuel tank must be fitted with a spring loaded safety relief valve mounted directly in
the vapour space of the tank. Safety relief valves shall be designed to start discharge and attain full flow at pressures in accordance with the design code of the fuel tank to which they are fitted with full allowance for the effect of extended discharge pipework. Reference should be made to LPGA Code of Practice No. 15 part 1.This requires relief valves to be marked with specified information which includes the set pressure.

 The discharge from safety relief valves shall be vented to the outside of the vehicle and
as far as practicable from possible sources of ignition and shall, in any case, be not
closer than 250mm from the exhaust system. The outlet shall be positioned in such a manneras to prevent impingement of escaping gas on any fuel tanks, and in any case of externally mounted tanks directed downwards, and in such a way as to prevent ingress of water. A captive raincap or other captive protector shall be used to keep water and dirt from collecting in the vent pipe but which shall not prevent free discharge when venting.

 Piping or ductwork used to convey the escaping gas from the safety relief valve shall
be of a material suitable for use with LPG and shall not reduce its maximum flow to lessthan that required. Elbows andbends can have a severe effect on flow. The minimum size of discharge line shall be 13.5mm  ID for containers up to 200 litres water capacity and 16mm for containers exceeding this capacity.
Such a discharge line shall be able to withstand the pressure resulting from the discharge
 of vapour when the safety relief valve is in the fully open position. It shall be of sufficient mechanical strength and adequately against physical damage or leaks.
 The piping or duct work connection to the relief valves shall be mechanically secured
 and shall not rely on adhesives etc for retention.

 Fixed Maximum Liquid Level Indicator.

  Where a maximum stop/fill valve is fitted, a fixed maximum liquid level indicator is
 not necessary.
The fixed maximum liquid level device, when fitted, should be suitable for use with the
 LPG stored and should indicate a maximum permitted fuel content at 80% tank volume.

 If the device relies on a bleed to atmosphere it should be so designed that the bleed
 hole does not exceed 1.4mm diameter.
The device should be designed so that the moveable parts of the device cannot be withdrawn completely n normal gauging operations.

 The bleed from the device should be extended to the outside of the vehicle, together
 with the fill pipe.

 Where more than one tank is fitted, each tank should have a separate fixed liquid level
 gauge. This is in order to prevent accidental over filling by inadvertently topping up
 already full containers in successive filling operations.
 Alternatively, this requirement may be relaxed if the system uses automatic switching of
 fuel supply to the engine between tanks every few minutes, or separate fill points
 to each tank.

 Contents Gauge. (Optional Fitting).
 Direct reading magnetic tape float gauges are recommended.
Contents gauges should clearly indicate FULL at 80%.
The sensing device of any indicator operated by an electrical system that may be exposed to LPG vapour should be of an approved construction for use in flammable atmospheres.
 All contents gauges materials should be suitable for the application with awareness of tank location. Those mounted under vehicles should not be manufactured from aluminium or other materials susceptible to salt spray.
 All wiring connections within the tank valve box should be adequately fixed and protected.

 A remote reading fuel gauge should be provided for dashboard mounting.

[Martin_1962]

Multiple Tanks.

 A single refuelling connection is normal for multiple tanks, and the fuel feed outlets are
manifolded to a single feed pipe to the engine. Appropriate check valves are therefore
 necessary at each tank connection to prevent flow between tanks.

 PIPEWORK-  LPG Pipelines.
 Pipelines or pipework for automotive applications are classified as “high pressure pipelines” if either are carrying LPG in the liquid phase, or carrying vapour in excess of 200mbar gauge. In either case, the pipelines and their assemblies shall be resistant to liquid phase LPG. Pipelines carrying vapour up to 200 mbar gauge are classified as “low pressure pipelines”.

 High pressure pipelines should be:-
 Seamless stainless steel to BS6362 or equivalent or,
Copper or copper alloy to DIN1787 or DIN17671 or equivalent or
Flexible fabric or metallic reinforced synthetic rubber or polymer hose designed for the
service pressure but not less than 25 bar gauge with a burst pressure not less than 125 bar
 gauge and to meet the criteria of ISO8789:1994.

 Engine compartment hoses should be suitable for an ambient temperature of 120 degrees
centigrade and need to be specifically warranted for this temperature as stated in        ISO8789. A lower temperature may be acceptable if approved by the vehicle manufacturer.

 Hoses shall be permanently marked as required by their specification standard and in relation to their test certificate.

  Low pressure pipelines may be rigid or flexible and in either case they shall be impervious and resistant to LPG in both liquid or vapour phase at the predicted operating temperatures.They shall be capable of sustaining at least 3.5 bar gauge without leaking or excessive distortion. If the operating conditions will involve an internal vacuum, they shall be capable of withstanding safely the maximum operating vacuum, or preferably a full vacuum, without collapse or undue distortion. Engine compartment flexible pipelines (hoses) shall be suitable for an ambient temperature of 120 degrees centigrade.  A lower temperature may be acceptable if approved by the vehicle manufacturers.

  Joints and Connections.

Every joint or connective fitting should be of metal and of a type suitable for service with
LPG at the operating pressure. This does not preclude the use of  suitable non-metallic
 seals within the fitting, complying with BS EN 549. Jointing compound for screw threads where appropriate shall be suitable for use with LPG and comply with BS6956 part 6 or 7 or pr EN751.

 The number of joints and connections should be the minimum for the melusion of essential components.
 Flared joints or compression union fittings with brass olives are preferred. Soldered or
welded joints and “bite” type compression unions should not be used.

 Fuel feed connections to engine mounted components need adequate flexibility to accommodate engine vibration. Flexible high pressure or low pressure pipelines as described previously may be used depending on the maximum operating pressure.

 Joint fittings and connections shall be compatible with one another and their mating
 materials shall not create electrolytic corrosion.

 Sizing of Pipelines.
The LPG liquid pipeline bore should be as small as possible to avoid undue rigidity and sufficiently large to provide for maximum engine fuel demand.

 It should be recognised that an excess flow valve incorporated into an LPG service valve
 will not protect the pipe in every eventuality, and it is therefore emphasised that the
 liquid pipeline should be as small a bore as practicable whilst meeting the maximum fuel
 requirement of the engine. In the event of a liquid feed pipe fracture, the engine will
 stop from a lack of fuel, and the electric valve at each tank will, therefore, be
de-energised to provide complete shut off.

 Pipeline Location.
 Every pipeline feeding from or into the fuel tank should follow the safest route and be
 protected from impact, preferably below the body shell where it may be shielded by
structural members of the vehicle.
 Pipelines should be remote from the vehicle exhaust system and not closer than 250mm.
 Where the requirement  of the above is not practicable, the pipeline must be shielded
from the vehicle exhaust system by a suitable heat shield.

 Pipelines should be effectively secured to the chassis frame or body shell at intervals
 of not exceeding 600mm and in such a manner to be protected against excessive strain
 and vibration. Pipelines shall not be installed where any part is permanently hidden from view and cannot be inspected regularly.
 The positioning shall be such that pipelines will not be affected by suspension or propshaft movement and shall not be located at jacking points.

 Flexibility.
 Pipelines shall be installed so as to take up safely the relative movement between
 chassis/body and the fuel system components and secured in such a manner so as to prevent wear taking place. All runs of rigid pipelines between components shall be installed with gentle curves, U bends or loops to provide flexibility.

[Martin_1962]

 Pipeline Over Pressure Protection.
Every section of LPG liquid pipeline between positive shut-off or lock-off valves should
 be protected against resultant damage from over pressure due to liquid thermal expansion.
Hydrostatic relief valves, where fitted, should be vented away from the vehicle exhaust
or people, to open air.

  LPG CONTROL EQUIPMENT
 Purpose.

 The control equipment comprises components which are necessary to supply the LPG in a state, either vapour or liquid, and at the pressure required by the engine design and the fuel management system and to ensure safe and efficient operation under all foreseeable modes of vehicle operation and use. Where an alternative fuel system is installed (bi-fuel), neither shall impair the safety or efficiency of the other.

  Components for all Engines.

 Installation

 The LPG control equipment should be:_
 Installed in positions that are easily accessible for routine inspection, maintenance and
 adjustment.Securely mounted and reasonably protected by location from accidental
 damage.As remote as possible from the engine exhaust system or protected therefrom by a heat shield. No closer to any electrical equipment capable of sparking than is avoidable.

Filter.
 Systems in which components are susceptible to mal-function or damage from solid
 particulate matter components. Some components have integral filters or devices.

Lock-off Valve.
 Immediately after any filter and upstream of any pressure reducing regulators there should be installedan efficient lock-off valve.
 The lock-off valve should be designed for automatic closure whenever there is no fuel
 demand from the engine.
 The lock-off valve should be capable of automatically opening to relieve excess hydrostatic pressure generated on the engine side of the valve.

  Automatic Safety Controls.

 Safety control systems shall be                by at least two means, either of which shall
cut off the LPG supply, and at least one of which shall operate if the engine stops
for any reason.

 Various methods can be adopted to meet these requirements. The following are examples:-

 A pressure regulator designed to give total closure on zero engine manifold depression.

A manifold pressure sensitive switch, normally open at zero depression, connected in series with the electric supply to the lock-off valve.

An oil pressure sensitive switch open for zero oil pressure, connected in series with the
 electric supply to the lock-off valve.

An ignition coil triggered switch in the electric supply to the lock-off valve which is
 open when the coil is de-energised.

 The electrical switches controlling the lock-off valve shall be connected in  series
With the electrical supply to the solenoid shut-off valves at the fuel tank(s) to provide
simultaneous shut-off.
 The electrical switch or mechanical means used to bypass a device as defined above to
facilitate engine starting or tuning should require continuous manual pressure to operate and should automatically return to the off position.

 For large passenger carrying vehicles see next section.

 Additional safety controls in the fuel system may be incorporated eg, inertia cut-off, tilt
switches, some of which are required by law for buses. See next section.

 Components for Non-fuel Injection Engines.
Vaporisers.

 Vaporisers for automotive use normally utilise heat from the engine coolant system.

  Where water circulation is employed.

 A continuous flow of water should be ensured which is not subject to interruption by
operation of the vehicle heater controls.

 The design of the water jacket of the vaporiser should take into account the possibility
of internal expansion resulting from water freezing and shall be resistant to antifreeze.

 The use of exhaust gas/LPG heat exchangers are not recommended.

 Every vaporiser should be constructed of materials suitable for use with LPG and be capable of withstanding the maximum pressure likely to be encountered in service.

  Pressure Regulators.
 LPG systems have one or two stages of pressure reduction. The pressure regulators and the vaporiser may be separate units but frequently are combined into a single unit referred
to as a converter.

The first stage regulator should reduce the pressure to a valve appropriate to the second
stage regulator inlet pressure.
The second stage regulator should be designed to give the pressure required at the
carburettor, gas-air mixer or injectors.
Every pressure regulator should be constructed of materials suitable for use with LPG and capable
 of withstanding the maximum pressure likely to be encountered in service.

  Carburettors and Adaptors.

 The Carburettor or adaptor is a gas/air mixing device in which the gas and air are metered in the correct proportions for combustion. The choice of carburation deprnds on the engine layout and application:-
 
Single fuel-  applies where complete conversion to LPG is effected, and a purpose designed LPG carburettor may be employed.

 Bi-fuel-  applies on an engine which may be supplied with an alternative fuel, normally
 petrol, the engine operating wholly on one or other fuel according to choice.

 Components for Vapour Phase Fuel Injection.

  Vaporiser.

 The fuel is changes to a vapour by the use of water heat and then is transferred under
pressure to a distribution valve that feeds the vapour to the injectors. The essential
 requirements are the same as for a non-fuel injection system.

 Distributor.

 The distributor shall be designed to provide the fuel to the injectors at the right time
 and quantity and linked into the electronic control system via the Lambda sensor,

 Safety.

 The unit shall be designed to fail safe in any condition and is triggered electronically.

 Components for Liquid Phase Fuel Injection.