Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: JamesV6CDX on 01 October 2007, 19:52:36
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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?
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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
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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?
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Did you dislodge any springs?
Do you still have Bernards phone number?
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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 :y
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
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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
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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
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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...
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Re: [lp-gas] Servicing Evaporators
Replace the two diaphragms. Watch out that the little connecting pin
moves freely as you reassemble.
Hugh
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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.
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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.
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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.
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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.
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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.
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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.
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Fuel Feed System.
The essential difference between the fuel feed system for a liquid fuel injection system
and a non-fuel injection engine (carburettor) or a vapour injection engine is the absence
of a vaporiser.
Fuel Feed Pump.
A pump is required to raise the fuel pressure, which will otherwise be at the vapour
pressure of the liquid in the fuel tank, to a sufficiently high pressure to ensure it
remains liquid throughout the fuel system allowing for heat gain in the vicinity of the
engine when running and to avoid hot restart problems due to heat soak after shut down,
or at switch over, if it is a bi-fuel system.
Pump external to the fuel tank. Feed from the bottom of the tank or from the top via
a dip tube. In either case the suction line should be gererous in diameter and as shot as
possible to avoid pump damage from cavitation.
Submerged pump in the fuel tank. This avoids the likelihood of cavitation.
Pressure Control.
To provide a constant feed pressure to the injectors, a pressure controller is normally
provided. This may form part of the management system of the engine or the
conversion equipment.
REQUIREMENTS FOR BUSES AND MINIBUSES
Regulations.
The Road Vehicle (Construction and Use) Regulations 1986 call for special requirements over and above those elsewhere in this Code relating to fuel systems for buses and minibuses. Some buses and minibuses may be classified as Passenger Service Vehicle (Conditions of Fitness, Equipment, Use and Certification) Regulations 1981, generally referred to as C.O.I.F., being the conditions of Initial Fitness. These also apply to some vehicles which are not buses or minibuses as defined but carry passengers who pay individually.
PSVs are required to be inspected by the Department of Transport, Vehicle Inspectorate,
Swansea, before entry into service.
This section applies to buses and minibuses, but if they are to operate as PSVs the legal requirements for the fuel system should be discussed with the Vehicle Inspectorate
Department of Transport at an early stage.
Where the following requirements are taken from the Passenger Service Vehicle (Conditions of Fitness, Equipment, Use and Certification) Regulation, they are indentified by (C O I F ).
Fuel Tanks.
The LPG fuel tanks, pipework arrangements, associated fittings and valves shall be located to comply with previous location guidelines and the following special requirements:-
Fuel tanks shall not be situated within 600mm of the entrance/exit on a vehicle with more than 12 passenger seats nor within 300mm of any entrance/exit on a vehicle with 12 passenger seats or less (C O I F 13).
Fuel tanks may be externally mountes or may be within the passenger compartment only if suitably enclosed and protected . (C O I F 13).
Fuel tanks mounted beneath a vehicle shall:-
Preferably be at least 500mm inboard of the sides of the vehicle or on the inside of the
chassis longitudinal frame members where applicable. If this location is not technically
possible, it is permissable to locate LPG fuel tanks outboard of this, but within the width
of the vehicle, in which case, suitable caging or structural fixtures shall be provided
to protect them and their associated fittings from severe side impacts.
Have adequate ground clearance in line with the vehicle manufacturers recommendations forladen and unladen use.
Fuel tanks for vehicles over 5 tonnes Gross Vehicle Weight shall be situated between the
front and rear axles.
Fuel tanks shall be situated as far as practicable from the exhaust system. If the clearance
is less than 250mm adequate shielding against heat radiation shall be provided.
Roof-mounted fuel tanks shall comply with guidelines already set out. PSVs need to be
assessed for the legal requirements for stability. (C O I F 6).
Tilt/inertia Cut-off switches (applies to all buses).
A vehicle tilt switch and an inertia switch are required both of which shall cause the electric solenoid valves at the outlet of each tank to close.
The tilt switch shall cause the fuel tank valves to close when the vehicle body angle of
tilt to the vertical is greater than 35 degrees for single deck vehicles, or 28 degrees
for double deck vehicles.
The inertia switch shall cause the fuel tank valves to close in the event of deceleration
of the vehicle exceeding 5g. The valves shall remain closed after actuation until the
inertia switch is manually reset.
Fuel Tank Fill Connection.
The filling point shall be accessible only from the outside of the vehicle (C O I F 13).
For vehicles with less than 12 passenger seats, the filling point shall not be at the rear
of the vehicle. (C O I F 13).
The fuel tank fill connection shall not be within 300mm of any door or other aperature
into the vehicle interior (C O I F 13).
The fuel tank fill connection shall not be located within 500mm of the exhaust outlet.
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how many times did you try it?
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Pressure Relief Valve (PRV) Discharge.
The discharge shall be directed downwards so as not to impinge on any part of the vehicle and shall be arranged as far as practicable so as to be clear at all times of the vehicle flooring, tyres, wheel arches, fuel tanks, manifolds and exhaust systems.
LPG Fuel System Relative to Vehicle Interior Apertures.
The design, location and installation of the LPG fuel system shall be arranged so that
no leakage from the LPG fuel system shall enter the vehicle interior.
The PRV discharge shall be directed as far away as is necessary from all openings and
apertures into the vehicle to avoid leakage into the vehicle interior and so as not to
interfere with people exiting from the vehicle in an emergency when the PRV may be venting and so that no fuel overflowing or leaking can accumulate on any woodwork or other part of the body such that it might be readily ignited.(C O I F 13 (2) ).
Fuel feed Pipe.
The LPG feed pipework shall comply with guidelines already set out and shall not pass through the passenger or driver compartments.
Manual External Fuel Cut-off.
A device shall be provided by means of which the supply of fuel to the engine can be
readily cut off. The means to cut off shall at all times be readily accessible from outside
the vehicle and shall be operated by hand. The location of the means of cut off shall be
clearly marked on the outside of the vehicle, and indication of the function and means of
operation to the cut off shall be provided nearby. The “off” position shall be clearly
indicated.(C O I F 13 (1) d).
The fuel cut off may be provided by any combination of the following:-
A manual device, accessible from outside the vehicle, which directly or indirectly closes
a valve in the LPG supply and simultaneously for a bi-fuelled vehicle, cuts off the
petrol feed.
Closing of the externally operated battery isolation switch (where provided), which in turn,
results 8in the closure of the valves.
Closing of an LPG fuel pipe manual valve located near to and upstream of the vaporiser.
Fuel Gauges.
A dashboard fuel gauge shall be provided. For multiple tanks one gauge for each tank is
recommended. They should read “FULL” at 80% of the tanks contents.
COMMISSIONING, MAINTENANCE AND INSPECTION
Installation and Commissioning
Installation and commissioning of the fuel supply system should only be carried out by and
supervised by LPGA “Approved” competent persons adequately trained in LPG automotive installation work and conversant with the properties of LPG.
Leak Test.
Except as described below , the complete system, including the tank(s) and all joints,
should be tested with air or inert gas at a pressure not less than 6 bar gauge, but not
more than 90% of the fuel tank design pressure. Soap solution or a proprietary leak
detection fluid, or other method of at least equal sensitivity, should be used.
If the fuel tank(s) and fittings are tested independently of the remainder of the system,
and charged with LPG, the remainder of the system should be tested separately as above
before connection to the tank(s) and the final connection(s) then leak tested at the
available tank pressure.
Charging the Fuel Tank and System with LPG.
Subject to the elimination of all leaks, the fuel tank(s) may be charged with LPG. It is
good practice to reduce the oxygen content of the tank(s) to 10% or less by volume before introducing LPG. This can be achieved by introducing an inert gas eg, nitrogen or carbon dioxide dilution of the air in the tank(s) until the required end point is reached. When charging the tank(s) with LPG, the inert gas/air/LPG vapour, should be vented or discharged in a safe place into the open air, and away from any sources of ignition. This shall continue until the inert gas/air has beeen eliminated.
Testing the Fuel System.
A final leak test should be carried out on any joints not previously tested under LPG
pressure, once LPG has been introduced.
Testing of controls under static conditions may be undertaken at this stage.
Road test.
Following the engine tuning, the vehicle should be given a thorough road test for
satisfactory performance. Bi-fuelled vehicles should be subjected to fuel change over
tests to ensure smooth transition.
Final Certificate and Documentation.
A competent person responsible for ensuring compliance with the Code of Practice and
relevant Statutory Regulations should, upon satisfactory completion of all tuning and
tests, issue a signed certificate of conformity for the purchaser.
The vehicle owner should be provided with a Drivers Operation Manual which should include the Certificate of Conformity with a recommendation that this is carried in the vehicle at all times, for examination by authorised enforcement agencies.
The vehicle owner should be informed that the Department of Transport, DVLA, need to be notified of the material change to the vehicle which must be noted on the vehicle
registration document.
Vehicle owners/operators need to ensure that a Special Vehicle Order has been obtained for any feature of the vehicle fuel system which does not comply with the Road Vehicle
(Construction and Use) Regulations 1986 or as amended. See “Foreword”.
Passenger Service Vehicle (PSV) operators need to apply to the Department of Transport
Vehicle Inspectorate, Swansea, to ensure the Certificate of Initial Fitness is valid for
putting the LPG fuelled vehicle into service.
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Vehicle Marking.
LPG powered vehicles should be fitted with a conspicuous durable marking informing that the vehicle operates on LPG and indicating the tank location and the position of the shut-off valves. The marking shall be of a durable type material. The marking should be displayed at the front and rear of the vehicle. The preferred locations are adjacent to the excise tax disc on the front of the vehicle and on the off-side windscreen at the rear of the vehicle.
Maintenance and Inspection.
The service manual for LPG fuelled vehicles should specify regular service requirements for the LPG fuel system or the additional requirements in the case od bi-fuelled vehicles.
Every service shall include a check of the condition of all valves and connections for corrosion, damage or leakage, and corrected or replaced as necessary.
At 5 year intervals – Flexible pipework should be replaced unless proved suitable for further service.
Fuel Tank(s).
Examinations and tests shall be carried out by a competent person.
Every 5 years an external visual examination shall be made of the tank(s) and its fittings including the pressure relief valve, for signs of deterioration, corrision or leakage.
Every 15 years - The tank(s) shall be subjected to an hydraulic pressure test and marked with the date and the testing authority symbol.
The accuracy of the 80% stop fill valve should be verified whenever the fuel tank is emptied by using a re-fuelling meter.
Garaging, Repair and Maintenance.
Vehicles fuelled with LPG may be parked, serviced and repaired inside garages provided that the following conditions are observed:-
Only trained and competent personnel on the use of LPG as a road vehicle fuel should be allowed to work on the vehicle engine or fuel system.
There shall be no leaks in the fuel system and the fuel tanks shall not be filled beyond
the 80% maximum level.
Such vehicles shall not be parked within 3m of sources of heat, open flames or other
sources of ignition.
LPG fuelled vehicles being repaired in garages, unless the fuel is required for engine operation, shall have the fuel tank(s) shut-off valve closed and the LPG fuel in the service line exhausted by running the engine or, if this is not possible, by disconnecting, in the open air, where the LPG cannot accumulate.
Vehicles undergoing repairs involving welding or the application of heat, to any part within 1m of the fuel tank, shall have the fuel lines emptied and the tank removed or shielded from the source of heat.
If the vehicle is to be repaired over an open pit, the pit shall be adequately ventilated.
It is recommended that lighting needs to be safe to use in a zone 2 area and that gas
detectors are permanently fitted at the bottom of the pit.
These should be checked daily.
Vehicles shall not be put through a low bake repainting oven or similar heating process unless the entire LPG system is safely removed or rendered gas-free.
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Transfer and Refit of the LPG Fuel System.
Whenever this takes place, the completed system should be tested and inspected prior to re-installation and rectification work, as necessary, carried out.
Demounted fuel tanks containing LPG should be handled with care and stored in accordance with Code of Practice No. 7.
All non-flexible pipelines should be replaced.
All flexible liquid phase hoses over 5 years old should be changed or re-tested in accordance with production proof tests in BS4089 or equivalent.
Consideration should be given to exchanging the relief valve of the fuel tank whenever it
might be refitted to a different vehicle or if vehicle ownership changes, whether or not this coincides with a 5 or 15 year inspection.
Vehicle Scrapping.
LPG fuel tanks must be removed from a vehicle before the vehicle is sent to be scrapped. Tanks should be handled with care and stored in accordance with Code of Practice No. 7 – “Storage of full and empty LPG cylinders and cartridges”. Tanks to be scrapped shall be destroyed in accordance with BS5430 by or under the supervision of a competent person and in a manner rendering them unserviceable for holding gas.
Hotwork.
No hotwork eg, welding, cutting or bending should be carried out on vehicles unless the risk of affecting the LPG tank or system has been eliminated. This may require the removal of the tank or system.
APPENDIX 1
PROPERTIES AND HANDLING LPG
All persons concerned with the storage and handling of LPG should be familiar with the
following characteristics and hazards:-
LPG is stored normally as a liquid under pressure, is colourless and its weight as a liquid
is approximately half that of an equivalent volume of water.
LPG vapour is denser than air, commercial butane being about twice as heavy as air and
commercial propane about one and a half times as heavy as air. Therefore, the vapour may flow along the ground and into drains, sinking to the lowest level of thesurroundings and be ignited at a considerable distance from the source of leakage. In still air any vapour will disperse slowly.
When mixed with air, LPG can form a flammable mixture: the flammable range at ambient temperature and pressure extends between approx. 2% of the vapour in air at its lower limit and approx. 10% of the vapour in air at its upper limit: within this range there is a risk of explosion. Outside this range any mixture is either too weak or too rich to
propagate flame, butat atmospheric, the upper limit of flammability is increased but the increase with pressure is notlinear.
Small quantities of the liquefied gas can give rise to large volumes of vapour/air mixture
and thus cause considerable hazard. A suitable, properly calibrated explosimeter may be used for testing the concentration of LPG in air. ON NO ACCOUNT SHOULD A
NAKED FLAME BE USED TO DETECT A LEAK.
LPG vapour is slightly anaesthetic and may also cause suffocation if present in sufficiently high concentrations.
LPG is normally odorised before distribution by the addition of an odorant such as ethyl
mercaptan or dimethyl sulphide, enabling detection of smell of the gas as concentrations
down to one-fifth of the lower limit of flammability (ie,approximately 0.4%of the gas in air). Escape of LPG may be noticeable otherwise than by smell. When the liquid evaporates, the cooling effect on the surrounding air causes condensation and even freezing of water vapour in the air. This effect may show itself as frost at the point of escape and thus make it easier to detect an escape of LPG. Because of the refractive index of LPG, leaks can sometimes be seen as a “shimmering”.
APPENDIX - REFERENCES
STATUTORY INSTRUMENTS ETC.
The Public Vehicle Act 1981
The Road Vehicle (Construction and Use) Regulations 1986 (and Amendments)
The Public Service Vehicle (Conditions of Fitness, Equipment, Use and Certification)
Regulations 1981 ECE Regulation 67
The Department of Transport Vehicle Inspectorate, Swansea.
STANDARDS.
BS 4089 Specification for hoses and Hose Assemblies for Liquefied
Petroleum Gas.
BS 5045 Specification for Steel Containers of 0.5 L up to 450 L
Part 2 Water Capacity with Welded Seams.
BS 5430 Periodic Inspection, Testing and Maintenance of Transportable gas Containers (Excluding Dissolved Acetylene Containers).
BS 6362 Specification for Stainless Steel Tubes suitable for Screwing
In accordance with BS 21. Pipe Threads for Tubes and Fittings Where Pressure-Tight Joints are made on the Threads
BS 6956 Jointing Materials and Compounds
Part 6 Jointing Compounds for 3rd Family Gases
Part 7 Anaerobic Jointing Compounds for 3rd Family Gases
EN 549 Specifications for Rubber Materials for Seals and Diaphragms
For Gas Appliances and Gas Equipment
Pr EN 751 Jointing Compounds (will supersede BS6956)
DIN 1787 Copper – Half Finished Products.
DIN 17671 Wrought Copper and Copper Alloy Tube Properties
ISO 8789 Rubber Hoses and Hose Assemblies for Liquefied
Petroleum Gas in Motor Vehicles. Specification.
CODES OF PRACTICE.
LPGA COP 15 Valves and Fittings for LPG Service
Part 1 Safety valves.
LPGA COP 7 Storage of Full and Empty LPG Cylinders and Cartridges.
FOREWORD
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FOREWORD
This Code of practice has been drawn up in consultation with the department of Transport. Motor Vehicles in the UK are required to comply with Road Vehicle (Construction and Use)
Regulations 1986 which includes specific requirements for LPG fuelled vehicles. These are supplemented by further requirements if they are to operate as Passenger Service Vehicles which are set out in The Public Service Vehicle (Conditions of Fitness, Equipment, Use and Certification) Regulations 1981.
All the above apply both to original manufacture and to subsequent modifications, such as LPG conversions.
An amendment to the 1986 Regulations during 1997, will, it is anticipated, mean that
compliance with this Code of Practice will also mean compliance with those Regulations.
Vehicles which do not comply with the 1986 Regulations, as amended, may only be used on the road by virtue of a “Vehicle Special Order” issued under Section 44 of The Road Traffic Act 1988 by the Department of Transport – Vehicle Standards and Engineering Division.
END OF COP11
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I suggest you cut and paste COP11 into one document!!!!
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As you can guess a lot of professional installs will not go through this, also why replace perfectly functional hoses.
I have seen no installs with the marked cut off vavles
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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...
Bernard - I gave you his number
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TheBoy goes and orders some more disk space after Martin Imber's mega postings :o
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TheBoy goes and orders some more disk space after Martin Imber's mega postings :o
:-[ :-[ :-[ :-[
It is only COPII