Experiences with Coal-gas—No. IV.
Page 7
Page 8
If you've noticed an error in this article please click here to report it so we can fix it.
A Representative Method of Fitting and Re-filling,
Following our references in last week's issue to Messrs. Chaprnan's road experience with coal-gas, we availed ourselves of an early opportunity to examine the working of his. Eastbourne-London-Eastbourne service.We ascertained that a gas-driven char-h-bancs leaves the Grosvenor Hotel, Victoria Station, London, each Tuesday and Friday morning at 10.45 a.m., and taking advantage of a vacant seat by the driver we coupled the pleasure of a short run on this undoubtedly-fine
• ehar-babarieso with the business of investigating personally the working of a long-distance trip an coalgas.
A Three-year-old Dennis Likes Coal-gas.
The vehicle is built on a Dennis chassis, and is the same one that for the last three years has been regularly engaged upon long-distance trips from Eastbourne to the popular touring „districts of South .Wales. Incidentally, in elicit;ng this item of information, we also obtained an unsolicited and disinterested testimonial to the running
of the Dennis chassis. , Points About .the. Holder and Its Cradle.
We were at the rendezvous some 15 minutes before the time to start, which period was occupied by an examination in detail of the arrangements for utilizing coal-gas as a fuel. The containeror flexible holder is one of Mr. Barton's standard fittings ; its capacity is 450 cubic ft., and it is carried upon a light wooden tray, itself supported by the. standards of the char-itbanes head. It may here be pointed out that the means for the support are simple indeed, ordinary mild-steel brackets being used,' which-may be manufactured by any
blacksmith. They need not be particularly heavy, as there is very little weight upon them, and the more gas there is in. the bag the less weight have these braekets to sustain. When the holder is full of gas it float's.
We might criticise the design of the cradle, inasmuch as it appears
to us that, it could be lightened considerably by making the base in lattice form, instead of as a complete floor ; alternatively, it seemed to us that the flooring might, very well be discontinued altogether for the greater part, and the weight of the bag taken, by the ;top of the hood.
Connections to Carburetter.
From the front of the container a large canvas pipe—somewhat like the arm or sleeve from a coat— leads to the brass union and cock which are utilized when refilling. A branch from this pipe leads to the carburetter. This is the ordinary type of iron gas-piping, and is so arranged that the controlling valve is readily accessible to the driver as he-sits in his seat ; as a matter of fact, it is quite close to the steering wheel. The pipe terminates at its delivery end in a piece of rubber hose, and is so arranged that the mouth is within a conical inlet pipe bolted to the White and Poppe carburetter, which is a standard fitting on this chassis.
The control of the fuel supply is a dual one. The accelerator pedal engageswith the throttle lever of the White and Felipe carburetter • it operates to regulate the mixed supply of gas and air." The gas supply itself is regulated direct by means of the small lever near to the steering wheel. There is not, as in previous arrangements, any direct eenpling-of the gas-supply lever to the lever on the throttle valve. Adjustment of gas and air is determined by the relativ,e position of 1 the end of the supply pipe within the conical inlet to the carburetter. It was evident from the behavioui. of the chassis on the read that the correct adjustment between the relative volumes of air and gas admitted has not yet been attained.
Driving Control on the Road.
The method of adjustment, it will be seen, is distinctly 'crude, and, at the same time, as the driver in formedus, the quality 61 the gas received varies considerably from point to point. It would appear, however, that tha difficulty 3£4 not so much one of adjustment of air to gas in order to meet the requirements of any specified quality of the fuel, but rather one of interconnection of gas-and-air control, so that the mixture can be regulated oontemporaneously with varying requirements of the engine. For example, on the occasion of our run, although satisfactorily meeting the needs of the engine at high speed or even when pulling under load at somewhat slower speed, upon acceleration, after stopping for any reason, or after a. short.period ef slow running, a little difficulty is eXperienced owing to what is popularly described as "popping back." This is noticeable ' whenever the throttle has been closed for any cause and is rapidly opened. It would seem as though Mr. Barton's arrangement, whereby the gascontrol lever and throttle-control lever .are inter-connected, is the better one.
We Make a Few Suggestions.
Where the vehicle is, as in the present instance, to be used for char-a-banes purposes (in which case the use of petrol is forbidden), it seems to us that a slightlydifferent arrangement might be adopted. Thiswould, however, vary with individual carburetters, and for the moment we will confine ourselves to suggestions applicable to the case of the White and Poppe, which, as is well known, has special features that will lend itself to the following :— That the gas supply be led direct to the jet. This will necessitate, of course, a very considerable enlargement of the orifice of the jet for the purpose of admitting sufficient of the fuel, and the arrangement is obviously not feasible where it may be desired f r o m time to time to use petrol. This, together with an inter -connection between throttle lever and gassupply lever, would, we feel sure, materially imptove t h e working of Messrs. Chapman's char-abanes, and especially in the circumstances to which we have referred, where a little difficulty in the regulation of the mixture is encountered.
In general, it is fairly obvious that a little less power is available than would be the case when using petrol. An earlier drop to lower gear is necessary than o n e naturally expects, b u t otherwise t h e running is very satisfactory.
Re-filling Points Overlap.
Messrs. Chapmae's arrangements are such that there is no fear, except in the most extraordinary Circumstances, of their ever being found without fuel.When we arrived at the first filling-station, at the gas company's premises, Croydon, there was still a considerable number of cubic ft. of gas left in the container. Incidentally, we may recall that the driver can readily ascertain the state of his fuel supply by a casual glance at the reflection of his vehicle, as it appears in the windows of the shops he may be passing en route.
Replenishing Arrangements at Croydon. •
Convenient preparation has been made op the premises of the Croydon'Gas Co. for the replenishing of the fuel supply iyith .as little delay as possible. A ikin. stand-pipe has been erected just inside the company's yard, which is screwed at its outer end to a suitable union "and cock which are carried at the end of the filling tube of the eons tamer. It is the work of a moment only, to make the necessary connections, and all that then remains is to open the two cocks—one on the gas pipe, one on the filling tube.. We illustrate these. The pressure here in the morning, owing to the fact that the company is then at what is called its cooking" pressure, is eqUivalent to 5 ins.ok water. The time .occupied in filling under these conditions is seven minutes. In the case of a call in the afternoon, when there is only
34 :4 of pressure, it may take so long as nine or ten minutes. The work of disconnecting the supply pipe is as simply and as readily per; formed as that of connecting it, when the char-h-hanes is ready to proceed on its journey. Interest in the process of refilling discounts the delay.