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"In the beginning", an appropriate phrase, given the near biblical amount of hurdles, obstacles and difficulties finally overcome in bringing the " dosing valve " to market. Back in the days when leaded fuel was fast disappearing from the garage forecourts and about to be confined to history, L.R.P emerged as the successor to four star and various lead replacement additives also made an appearance. These additives, designed to be added to the fuel in measured doses each  time the tank was filled or part-filled. All this to prevent the onset of the dreaded valve seat recession ( V.S.R).

The above presented the user with several problems:-

1) How many lead replacement additives were available.

2) What were the base chemical constituents of these additives.

3) Which was the preferred option.

4) Should and could different additives be mixed

5) Which type of additive was used in the L.R.P pump at the forecourt.

6) Did different fuel companies use different additives in their L.R.P pumps.

7) Was hand dosing an additive to the fuel tank -

              a) accurate

               b) convenient.

               even given the container was clearly calibrated

8) What if the additive normally used was not available at a particular filling station.

To add to the confusion several "devices" and I use the word advisedly, appeared on the market, each claiming to have inbuilt properties which could in some way allow unleaded fuel to be safely used. It is not my intention to dwell on, or devote further space to these " products ".

There appeared to be four options available to the owners of vehicles which had previously been reliant on leaded fuel :-

1) Some engines by minor carburettor adjustment could safely run on unleaded.

2) Continue to use leaded fuel if and where available.

3) Take the vehicle to a reputable garage, have the engine stripped down, fit hardened valve seats and rebuild. This method while solving the problem, was and remains expensive, engine size and complexity adding to the cost. Some owners preferred not to prejudice engine integrity by so doing, others required specialist firms to undertake such work and the unfortunate, because of the build nature of their engine, unable to have this work completed, even if they had so wished.

4) Lead replacement additive dosing valve. This appeared to be the best and most cost effective option, so with this in mind it was decided to design a valve which could accurately and automatically dose a measured and required amount of lead replacement additive " in line" to the main fuel line, pre carburetion, in order that an accurately mixed and consistent additive-to-fuel treat would be presented to the carburettor at all times. It was further considered that a precision valve with integral reservoir, manufactured to a very high specification but with an acceptable price tag, would be infinitely preferable to having to calculate, measure and manually  feed additive to the tank on each fuel fill. It would also be a welcome alternative to expensive engine modification.

 

The brief was then clear and the first step towards bringing the E.L.N dosing valve to market was taken.

The design criteria for dosing valve and manufacture were as follows :-

1) In line operation.

2) Simplicity of design and operation.

3) Dosing accuracy.

4) Reliability.

5) Automatic dosing.

6) Cost of manufacture.

7) Ease and simplicity of installation.

8) weight and type of materials.

9) volume production repeatability on tolerances.

10) Coating and metal finish, internal and external.

11) Robust yet sensitive in operation.

12) Integral safe guards.

13) Carriage costs

14) Retail costs.

Five methods of in-house valve design were investigated and subjected to comprehensive, rigorous, technical and theoretical investigation :-

1) Vacuum ( fuel line control )

2) Vacuum ( inlet manifold control )

3) Filler pipe, to fuel tank ( turbine control )

4) Electro mechanical ( in line )

5) Mechanical, flow sensitive control, ( in line )

Only one appeared to satisfy the required design criteria. ( No 5 )

The others were discounted for many reasons including:-

1) Overly complex

2) Standardisation.

3) cost of manufacture

4) Retail cost

6) Difficulty of installation

7) Difficulty in manufacture.

8) Reliability of operation.

It has taken in excess of five years to bring the original concept to production. Early prototype models working and non-working of the mechanical " in line " dosing valve were produced. Several years of detailed tests, revised prototype models, modifications, refinements, redesign, calculations, recalculations, world wide patent submissions and yet more tests and test figure analysis were completed, as the valve developed and changed in appearance both internally and externally. Finally the E.L.N. dosing valve was completed in production form and is now available to the world market.