GB2461375A

GB2461375A - Controlling supply of gaseous fuel supplement to an i.c. engine

Info

Publication number: GB2461375A
Application number: GB0910437A
Authority: GB
Inventors: Thomas Wing Kin Lam
Original assignee: BTRACK SOLUTIONS Ltd
Current assignee: BTRACK SOLUTIONS Ltd
Priority date: 2008-07-01
Filing date: 2009-06-17
Publication date: 2010-01-06
Anticipated expiration: 2029-06-17
Also published as: GB0910437D0; WO2010001086A1; GB0811935D0; GB2461375B

Abstract

The supply of a gaseous fuel supplement, eg hydrogen, to an i.c. engine, eg a diesel engine, is varied in proportion to engine load, eg estimated using engine rpm. The hydrogen may be generated by a solid polymer electrolyte (SPE) hydrogen generator with a distilled water/polymercatalyst electrolytic cell and. The supply of hydrogen may be regulated by varying the electrical current flowing through the SPE generator, eg by varying the applied voltage. The hydrogen concentration at the air intake may be controlled to be 5% or less and the oxygen may be injected separately from the hydrogen. A fuel blending system for a combustion engine comprising this control apparatus is also claimed.

Description

Fuel Blending System and Method

Field of the Invention

The invention relates to a hydrogen-blending fuel system for combustion engines. In particular, the invention relates to a control system for a hydrogen-blending of petro-chemical fuel such as diesel or petrol.

Background to the Invention

In the art, it is known to deliver hydrogen to the combustion chamber of an in internal combustion engine in order to improve efficiency of combustion. Typically, this may be accomplished by injection of the hydrogen through the air intake system of the combustion engine. The system/apparatus for such methods is sometimes referred to as a hydrogen enrichment unit.

Electrolysis of distilled water with the aid of alkali and using electrolyte supplied with current to produce oxygen and hydrogen is known.

Many conventional systems for blending hydrogen into fuel either use a reservoir of hydrogen carried in the vehicle, or use conventional electrolytic generation of hydrogen. Applications involving the supply of hydrogen that is produced by the electrolysis of distilled water and then using the hydrogen produced to blend into the air intake of a combustion engine for more efficient combustion, are known. These systems typically need to be externally powered with high current electronics to supply the electromotive force to the electrolysis rods. Furthermore, complex buffering systems may be needed in order to optimise electrolysis. This can add costs, and can lead to further complications in terms of chemical hazards when such devices are fitted to vehicles. * * S..

Prior art based systems typically continuously supply hydrogen to the combustion : *. engine. In the prior art, where a system is used to regulate the supply of hydrogen, this S...

is typically confined to a simple "on" / "off" switch. Conventionally, hydrogen is supplied at a constant flow rate when the engine is on or running. * *. * S * S **

Hydrogen enrichment units that use the conventional electrolysis of distilled water using alkali as catalyst are known. These units are applied in combustion engines and in the motor industry. These systems rely on detection of the "ignition on" or the "alternator signal on" to start producing the hydrogen for blending to the air intake of the combustion engine.

These known systems will only produce a fixed rate of hydrogen output once they detect the "ignition on" or the "alternator signal on". The rate of fixed hydrogen output will depend on the fixed current supplied and the size of the electrolysis chamber. This method of supplying the hydrogen blending is only controlled on the most crude level because the same volume of hydrogen will be produced when the engine is idling at low RPM as when the engine is revving at, for example, 2000 RPM or more.

This crudely regulated blending (crudely regulated supply of hydrogen) can have numerous drawbacks. For example, at idling speed, there is the possibility of an over supply of hydrogen. Oversupply of hydrogen, hydrogen being a very combustible gas, can cause the piston to over work. This can lead to explosion of the combustion chamber. There are known incidences of a prior art hydrogen blending system that exploded due to over supply of hydrogen because the vehicle key was left in the "ignition on" position without cranking the engine.

A further problem with known systems and their over supply of hydrogen is wasted hydrogen generation. As well as the dangers outlined above, there is also wasted energy in generating the oversupplied hydrogen. Furthermore, there is correspondingly more electrolyte/distilled wafer used with extra cost and shorter periods between eletrolyte/distilled water refills.

A further problem with known systems is that at higher RPM, when there are therefore higher fuel and air requirements for the combustion process, the conventional hydrogen blenders cannot supply the correct hydrogen blending for the vehicle combustion chamber. This has the effect that they do not produce optimum combustion, which leads to poorer fuel consumption (mpg) and higher exhaust emissions. * * *.**

*. A further problem with electrolysis-based hydrogen generation in vehicular hydrogen S. SS blending systems is that the unit can be cumbersome and large, leading to increased fuel costs in transporting the unit around together with the vehicle. * *S * . I * S.

The production of hydrogen and oxygen using SPE (Solid Polymer Electrolyte), without the addition of alkali, which is done using less energy and lower heat emission during the process of hydrogen generation is the subject of a patent application by the Chinese company Shandong Saikesaisi hydrogen Energy Co Limited in Chinaof 1999.

The patent number is ZL 98222451.0.

The present invention seeks to overcome problem(s) associated with the prior art.

Summary of the Invention

In contrast to prior art based systems, the present invention is based upon the use of active control of the hydrogen source in order to vary the flow of hydrogen into the combustion engine. Specifically, it is a key advantage of the invention that the volume of hydrogen injected into the engine is dependent on the work rate of the engine, such as the revolutions per minute (rpm) of that engine.

Thus, in contrast to the prior art uses which have only been able to provide a constant supply of hydrogen, the present invention is based upon variable on demand supply of hydrogen to the combustion engine. Thus, according to the present invention, the supply of hydrogen can vary dynamically over time, and in particular can vary dynamically in response to the load placed on the engine, for example, in accordance with the rpm of that engine.

Thus in one aspect the invention provides a control apparatus for regulating the supply of gaseous fuel supplement to an engine wherein the control apparatus is configured such that; in use, the supply of gaseous fuel supplement to the engine is varied in proportion to the load on the engine.

Suitably the supply of the gaseous fuel supplement to the engine is continuously variable. Suitably the supply of the gaseous fuel supplement to the engine is able to be varied dynamically in proportion to the load on the engine. In other words, suitably the supply of the gaseous fuel supplement to the engine can be varied in incremental *...* 30 steps, or continuosly if using an analogue system, over at least about ten different settings or flow rates of the gaseous fuel supplement. Suitably supply of the gaseous ::::. fuel supplement to the engine is controlled over at least about 20 steps, suitably at least about 50 steps, suitably at least about 100 steps or even more. By continuously' is meant that the supply of the gaseous fuel supplement to the engine is able to track the * *. 35 load on the engine (such as RPM) in a close-coupled arrangement so that the supply mirrors or follows the engine speed. Suitably the supply is regulated directly proportionally to the engine speed.

Suitably the load on the engine is the engine speed in revolutions per minute (rpm).

Suitably the gaseous fuel supplement is hydrogen.

Suitably the source of gaseous fuel supplement comprises a solid polymer electrolyte hydrogen generator.

Suitably the control apparatus regulates the supply of gaseous fuel supplement by controlling its production from a solid polymer electrolyte hydrogen generator. Suitably said control comprises varying the electrical current flowing through the solid polymer electrolyte hydrogen generator. Suitably the electrical current is varied by varying the proportion of time for which a constant voltage is applied to said solid polymer electrolyte hydrogen generator. More suitably the electrical current is varied by varying the voltage applied to said solid polymer electrolyte hydrogen generator.

Suitably the combustion engine is a diesel internal combustion engine.

In another aspect, the invention relates to a fuel blending system for a combustion engine, said system comprising a source of gaseous fuel supplement, a supply system for introducing the gaseous fuel supplement to the engine, and a control apparatus as described above.

In another aspect, the invention relates to a vehicle comprising a control apparatus as described above or a fuel blending system as described above.

In another aspect, the invention relates to a method of operating a fuel blending system for a combustion engine, said method comprising *: : : : monitoring the engine load *.*. 30 supplying a gaseous fuel supplement to the engine wherein the gaseous fuel supplement is supplied to the engine in an amount ::::. proportional to the engine load In another aspect, the invention relates to a computer program product which, when 35 operating a computer, is capable of carrying out the method as described above.

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In another aspect, the invention relates to a controller which is capable of carrying out the method as described above.

Detailed Description of the Invention

The invention may be applied to any suitable fuel blending system. The invention is most conveniently applied to gas-based fuel blending systems. For example, the invention may be applied to nitrous oxide or hydrogen fuel blending systems, most suitably to fuel gas blending systems such as hydrogen fuel blending systems. It should be noted that nitrous oxide is not a fuel gas since it does not contribute combustible material but rather contributes available oxygen and therefore operates by a different mechanism and is not considered to be a fuel gas. Suitably the gas is hydrogen.

The hydrogen source may be any suitable source of hydrogen known to those skilled in the art, The hydrogen source may be a reservoir or canister of hydrogen. The hydrogen source may be an electrolytic cell used to generate the hydrogen. The hydrogen source may be a distilled water/polymercatalyst hydrogen generation system such as that described in Chinese patent document ZL 98222451.0. Most suitably, the hydrogen source is a distilled water/polyrnercatalyst system as disclosed in Chinese patent document number ZL 98222451.0 or publication number CN 101289747.

It is an advantage of the invention to apply a distilled water/diaphragm based hydrogen source in a vehicular fuel blending system, since this results in a safer apparatus by eliminating the need for chemical electrolytes to be carried as part of the hydrogen source. It is an advantage to use distilled water/polymercatalyst hydrogen sources in vehicular applications since they can be smaller than conventional electrolytic hydrogen sources, thereby saving weight and space in the vehicle. In addition, there is less heat generated by the use of distilled water/polyrnercatalyst hydrogen generator and thus a simpler and/or lower requirement to dissipate the heat out of the electrolysis chamber resulting in a smaller unit according to the present S...

* * *. invention. S* S *. * . S...

Hydrogen flow to the combustion engine may be regulated by any suitable means known in the art. For example, the regulation may be by conventional variable valves, or by pressure control, or by control of flow rate into the engine system. Alternatively, the amount of hydrogen may be controlled by varying its concentration within a unit volume of air introduced into the combustion engine, or by maintaining a constant concentration within a varying volume of air introduced into the combustion engine.

Suitably, the amount of hydrogen entering the combustion engine is controlled by manipulation of the hydrogen source. Most suitably, the hydrogen source which is controlled is a hydrogen generator, most suitably a distilled water/polymercatalyst hydrogen generator.

Suitably the control of the amount of hydrogen entering the combustion engine is carried out by a telematic system which varies the volume of hydrogen injected in accordance with the RPM of the engine. Suitably, the volume of hydrogen injected is controlled by manipulation of the amount of hydrogen generated.

Suitably, when the hydrogen source is a distilled water/polymercatalyst hydrogen generator, the volume of hydrogen injected is varied by varying the amount of hydrogen generated. Suitably, the amount of hydrogen generated is controlled by varying the amount of current flowing through the distilled water/polymercatalyst hydrogen generator.

Suitably, the electrically active surfaces of the polymercatalyst of the hydrogen generators are operated at a variable voltage. In view of the variable voltage, and in view of an essentially constant resistance within the generator, the current is therefore varied proportionately in the hydrogen generator in this type of control system. This is advantageous in that it ensures that the hydrogen generation system is always operated at the optimum voltage, whilst allowing precise control over the volume of hydrogen generated by switching the voltage and therefore causing variation in the current and variation in hydrogen emitted, The prior art view of "on demand" hydrogen supply is simply an on/off variation. In sharp contrast, the present invention teaches widely variable hydrogen production, the rate of hydrogen production being carefully tailored to the activity or load on the engine being supplied. In the context of the invention, the load on the engine is conveniently estimated using the revolutions per minute (RPM) of the engine. * * * ** *

*, 30 The telematic control system must have a means for detecting the load on the engine **.* (RPM). In one embodiment, RPM information may be acquired by the control system from an on board computer such as the engine management computer. In another embodiment, the engine load (RPM) information may be collected by the control system of the invention via simple conventional RPM input (e.g. pulse counter). * S.

* . * 35 S ** The system is suitably used to control the amount of hydrogen supplied to the engine by increasing the amount of hydrogen as the load (RPM) of the engine increases. In other words, suitably the flow of hydrogen into the engine is directly proportional to the load on the engine as estimated by the engine speed or RPM.

The invention may be applied to any internal combustion engine. The invention may be applied to any pefrochemically fuelled engine. For example, hydrogen blending may be applied to diesel engines or to petrol engines, most suitably to diesel engines.

The invention may be applied to any combustion engine for any static or dynamic application. Suitably, the invention is applied to vehicular combustion engines.

Suitably, the invention is applied to engines in heavy goods vehicles, vans or cars. Most suitably, the invention is applied to engines in heavy goods vehicles.

Suitably the system requires an electrical power supply. Advantageously, this may be supplied from the vehicle when the system is installed in a vehicle. Advantageously, the system of the invention is a low wattage power consumption unit.

The system of the invention suitably comprises a hydrogen feed pipe from the hydrogen source to the air intake of the combustion engine.

Hydrogen is a flammable gas. High concentrations of hydrogen in a hydrogen-air mixture can lead to a risk of ignition or explosion. In this regard, advantageously the hydrogen concentration introduced into the air intake of a combustion engine is approximately 5% or less. By controlling the proportion of hydrogen to be 5% or less, the risk of explosion is minimised or eliminated. For similar safety reasons, the oxygen generated by an electrolylytic hydrogen generator is injected into the engine separately from the hydrogen. Optimally, the hydrogen in the air intake is regulated to approximately 1% by volume of the air taken in by the combustion engine, while commercially significant benefits in terms of fuel economy and emission control may be * : achieved at substantially lower hydrogen injection levels, for example one or Iwo orders *. 30 of magnitude lower. S..

:.. When the hydrogen source is a distilled water/polymercatalyst hydrogen generator, suitably the distilled water is high purity distilled water. More suitably, the distilled water is steam-distilled water. Suitably the distilled water reservoir is of a suitable size to allow *. : . 35 at least about 15,000 miles in between maintenance or top up operations.

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Suitably, the system of the invention further comprises an indicator light visible to the driver of the vehicle in which the system maybe installed. Suitably this indicator light is arranged to inform the driver if there is a problem with the system such as if the hydrogen source needs to be replenished, for example, topped up with distilled water.

Suitably the system of the invention may further comprise an alarm capable of informing the driver in the event of failure of the system such as a blockage in the hydrogen feed pipe. It is an advantage of the invention that in the event of a failure of the hydrogen supplementation system, the combustion engine will still run (albeit with a lower efficiency/higher emission characteristic than when the system is operational).

Suitably, the distilled water/polymercatalyst hydrogen generator is a solid polymer electrolyte (SPE) type hydrogen generator. Suitably the hydrogen source comprises the low energy SPE electrolysis process (see patent document ZL 98222451.0 or publication CN101289747) to produce the required hydrogen (i.e. hydrogen enrichment) for the combustion engine air intake. This advantageously permits the electrolysis chamber to be much smaller than the conventional hydrogen blender.

Suitably the system of the invention is linked to an "ignition sensor" and/or to an engine RPM sensor". If the RPM sensor only reads out signal when the engine is running then it may be possible to omit the ignition sensor. Nevertheless, suitably both sensors are used. The apparatus of the invention controls the power supply to the hydrogen source (Hydrogen Generation Unit (HGU)). The apparatus is arranged to monitor the RPM of the engine and in turn regulate the current supply to the HGU. This way, when the key is put to the "ignition on" position without cranking. there will be no current supply to the HGU.

When the engine is cranked and the RPM is detected, the power supply will provide a certain amount of current to the HGU according to a fable. An exemplary table is provided in the examples section. This in turn is interpreted by the HGU and a certain * S..

: amount of hydrogen output is produced for hydrogen enrichment (i.e. supply to the *. 30 engine). Thus when an engine such as a vehicle engine is idling it will receive a different : hydrogen blend compared to when the vehicle is revving at (for example) 2000 rpm.

S... . In one embodiment, the invention may be used to achieve fuel sayings of up to 15%.

*:*::* 35 In some embodiments, the invention may be used to achieve emissions reductions of up to 45%.

In one embodiment, the invention relates to a method for control of a hydrogen fuel blending system comprising determining the engine speed, and varying the amount of hydrogen supplied to the fuel blending system in proportion to said engine speed.

In one embodiment, the invention relates to a control system comprising an array of electronic components as shown in the accompanying drawings.

The benefits of using hydrogen-blended fuel systems according to the present invention in combustion engines include better fuel consumption and/or decreased emissions.

Thus, the benefits of variably regulating the hydrogen output according to the present invention include provision of more optimum blending and thus better fuel consumption at different engine revs. Moreover, the invention provides lower harmful exhaust emissions. Furthermore, the invention advantageously provides a longer period between distilled water/electrolyte fill ups due to avoiding wastage.

Known hydrogen blending systems provide constant supply of hydrogen to the combustion chamber irrespective of the speed of the engine and therefore the "air/fuel ratio" is not blended efficiently. This results in "incorrect blending" and thus more incomplete combustion and more harmful exhaust emissions. By contrast, the present invention provides superior emissions control using dynamically variable hydrogen supply dependent on engine speed.

Brief Description of the Drawings

Figure 1 shows schematically in perspective a controller according to the present invention having a hydrogen output display and LED alert with a lockable cover; and having shock absorbers for mounting the controller to the structure of a vehicle. S... * * . ** *

30 Figure 2 shows a table for adjustments to suit different engine types; and shows a block diagram of a system according to the present invention with numbered features 1 to 8 that will be self-explanatory to persons skilled in the relevant technology, who will readily be able to select suitable components for constructing the indicated power supply circuitry, and for conveying the generated hydrogen and oxygen and injecting *:a::: 35 them respectively into the engine. **** S *

The invention is now described by way of example. These examples are intended to be illustrative in nature, and are not considered to limit the scope of the appended claims.

Examples

Example 1

In this example the hydrogen source comprises the low energy SPE electrolysis process (see patent document ZL 98222451.0) to produce the required hydrogen (i.e. hydrogen enrichment) for the combustion engine air intake.

The system comprises a controller which is linked to ignition sensor" and "engine RPM sensor". The system controls the power supply to the hydrogen source (Hydrogen Generation Unit (HGU)). The apparatus is arranged to monitor the RPM of the engine and in turn regulate the current supply to the HGU. This way, when the key is put to the "ignition on" position without cranking, there will be no current supply to the HGU.

When the engine is cranked and the RPM is detected, the power supply provides a certain amount of current to the HGU according to a table. This in turn is interpreted by the HGU and a certain amount of hydrogen output is produced for hydrogen enrichment (i.e. supply to the engine). Thus when an engine such as a vehicle engine is idling it will receive a different hydrogen blend compared to when the vehicle is revving at (for example) 2000 rpm.

The following table is suitably engineered or more suitably programmed into the apparatus of the invention to control the power supply to the hydrogen source.

Engine RPM Current (AMPS) mI/mm Hydrogen

--0 0 0

1-600 0.8 50 601-750 1.2 75 S...

.. : 751-900 1.7 100 901-1050 2.1 125 S...

1051-1200 2.5 150 1201-1350 2.9 175 1351-1500 3.3 200 1501-1650 3.7 225 *:::* 1651-1800 4.2 250 S 1801-1950 4.6 275 1951-2600 5.0 300 >2600 S 5.0 300 Of course, the skilled operator may optimise these figures depending upon the specific application to which the invention is being put, and larger or more prolific HGUs may be used to suit larger engines and/or to provide higher rates of hydrogen injection.

Example 2

The invention is easily adapted for different engine types. For example, engines can be classified into different bands according to their applications The 3 bands (A, B and C) shown in Figure 2 allow for finer adjustments to hydrogen production for various RPM bands. Heavy trucks will require different amount of Hydrogen compared to say Vans and cars, other heavy static combustion engines.

Other bands may be calculated for other applications. It must be noted that the A/B/C band selector is an example for illustration. In some embodiments, we provide up to 9 fable selection, or even more.

Reciarding the RPM band selector (bands A/B/C in this example): Reference is made to the numbers in the different columns (bands A, B and C) and the highlighted 1 50m1 hydrogen row in Figure 2.

A variable band selector is an advantageous feature of the controller of the invention.

The benefits include adaptability of a single controller to different engine types or applications. For example, at a specific cruising speed of a truck and at RPM for example 1350 rpm, it will require more hydrogen as the air/fuel ratio for a truck combustion chamber is different to that of say a car cruising at the same RPM (e.g. 1350 rpm). Thus by providing an RPM band selector as part of the controller of the invention, the controller may advantageously be quickly and easily adapted for use S...

with different enginetypes or sizes or applications. Of course controllers of the invention may be produced without a RPM band selector. These embodiments may be cheaper to produce since they will not require the band selector component, and will be adapted only to a single engine type or application. Most suitably the controller of the invention comprises a RPM band selector.

*: *: 35 In this example, reference is made to the fable of Figure 2 for Bands A, B and C. S.....

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For a truck, Band A may be selected. When the truck engine is at 1350 rpm. the system will produce 175 mI/mm hydrogen to the combustion engine to produce optimum combustion.

For a car, Band C may be selected. When the car engine is at 1350 rpm, it will produce mI/mm hydrogen to the combustion engine to produce optimum combustion.

These band table figures may be optimised by the skilled worker, and/or different bands introduced for different applications or engine types. Values may be chosen by testing for optimum combustion and/or emissions as noted above.

The highlighted 150m1 Hydrogen is for calibration of the RPM to the hydrogen output.

So when a new vehicle is first fitted with the system of the invention (Hydrogen Enrichment Unit), it is suitably calibrated by adjusting the RPM pulses to the hydrogen output. Different vehicles will have different "pulses per Rev" depending on the number of cylinders or other factors. Of course when the RPM is obtained from a non-pulse source e.g. from the engine management computer, then such calibration may be simplified or unnecessary.

To calibrate the system for a vehicle, the engine is adjusted up to 1200 RPM (for Band A engines). The "RPM trimmer" is then adjusted, or the current output is to the hydrogen generator is adjusted, until the output is 1 50m1/min. In this way, we can calibrate the engine RPM to the hydrogen output requirement of the combustion engine to produce optimum combustion.

All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described aspects and embodiments of the present invention will be apparent to those skilled in the art without departing from the scope of the present invention. Although the present invention has * ,* * *,,,,. 30 been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are apparent to those skilled in the art are intended to be within the scope of the following claims. *-35

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Claims

Claims 1. A control apparatus for regulating the supply of gaseous fuel supplement to a combustion engine wherein the control apparatus is configured such that, in use, the supply of gaseous fuel supplement to the engine is varied in proportion to the load on the engine.
2. A control apparatus according to claim 1 wherein the load on the engine is the engine speed in revolutions per minute (rpm).
3. A control apparatus according to any preceding claim wherein the gaseous fuel supplement is hydrogen.
4. A control apparatus according to claim 3 wherein the source of gaseous fuel supplement comprises a solid polymer electrolyte hydrogen generator.
5. A control apparatus according to claim 4 wherein the control apparatus regulates the supply of gaseous fuel supplement by controlling its production from a solid polymer electrolyte hydrogen generator.
6. A control apparatus according to claim 5 wherein said control comprises varying the electrical current flowing through the solid polymer electrolyte hydrogen generator.
7. A control apparatus according to claim 6 wherein the electrical current is varied by varying the voltage applied to said solid polymer electrolyte hydrogen generator.

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8. A control apparatus according to any preceding claim wherein the combustion * p.* * 30 engine is a diesel internal combustion engine.

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9. A fuel blending system for a combustion engine, said system comprising a source of gaseous fuel supplement, a supply system for introducing the gaseous fuel supplement to the engine, and s 35 a control apparatus according to any preceding claim. * 4
10. A vehicle comprising a control apparatus according to any preceding claim or a fuel blending system according to claim 9.
11. A method of operating a fuel blending system for a combustion engine, said method comprising: monitoring the engine load; supplying a gaseous fuel supplement to the engine; wherein the gaseous fuel supplement is supplied to the engine in an amount proportional to the engine load
12. A computer program product which, when operating a computer, is capable of carrying out the method of claim 11.
13. A controller which is capable of carrying out the method of claim 11.
14. A system, apparatus or method substantially as described herein.
15. A system, apparatus or method substantially as described herein with reference to the accompanying drawings. * * * ** S S... * S *SSS * S. * S S *.SS * S. * I S * *.S*S.S.SI S