Australian Exhaust Brake in Action
Page 54
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I HAVE just seen an article which appeared in The Commercial Motor of January 11, 1957, under the heading "Exhaust Brakes Raise Bore Wear," and published as a report from Australia. As the inventor and patentee of the " Pavey " exhaust brake, also as a qualified automotive engineer with some 50 years' practical experience, I consider myself qualified to offer comment on this matter.
Judging from the report of the paper read by Mr. W. A. Snell and Mr. T. I. Fowle at a meeting of the Midlands Centre of the Institute of Road Transport Engineers, the authors were evidently not aware of what happened at the World Conference of the Shell Petroleum Company's transport engineers, held recently in London, and the views expressed there by an Australian representative regarding the use of an exhaust brake.
As a matter of fact, the Shell Company of Australia, in New South Wales, Victoria and South Australia, have had Pavey exhaust brakes in use for over a year. They subjected them to the most stringent tests, and have found them completely satisfactory in „operation, with none of the detrimental features mentioned in your report. The Queensland branch of the company are showing a keen interest in the brake after making extensive inquiries from their organization in other States.
I quite agree with the reply of Clayton Dewandre Co., Ltd. (per Mr. A. G. Parrett), as far as it goes in the matter, viz. "That the possibility of fouling gases being forced past the piston rings at such relatively low pressures as used in the engine when the exhaust brake
is in operation is highly improbable." I would go further, however, and say that the only possible reason for any exhaust gases being present in the cylinders when the brake is applied would be because the fuel is not being completely cut off before the brake valve is closed.
I believe that there are some types of exhaust brake on the market which do not completely cut the fuel supply and, therefore, in such cases it is possible for crankcase dilution to take place.
Moreover, some exhaust brakes on the market, by employing the butterfly type of valve, offer resistance to the natural passage of exhaust gases during the normal running of the engine, and although the area containing the valve is increased in an attempt to overcome the resistance of the mass placed in the normal path of the exhaust gases, this may not achieve its objective, as the direct flow of gases is interrupted and turbulence must occur.
In the Pavey exhaust brake the brake box is designed so that the valve and operating arm are recessed into the wall of the box, leaving an unobstructed straight line of exhaust the full area of the particular exhaust system of the vehicle to which it is fitted. The fuel is definitely cut off at least 20 degrees before the brake valve is closed.
I would like to make it clear that this exhaust brake has been fitted to trucks operating in mountainous country, logging and inter-State hauling in Australia for the past five or six years, as well as to heavy earthmoving equipment such as Euclids, with very beneficial results.
A report from a reputable Melbourne firm of engineers, who gave their findings after overhauling a B20 vehicle which had completed 100,000 miles on mountain work with the Pavey brake in use, stated that there was no sign of damage through the use of this brake, and the brake itself did not require servicing.
Berala, New South Wales, Australia. E. A. PAVEY.
The Conversion of Janus
Y could hardly fail to see the advantages of co-operation with each other. Many of them had served their term with British Road Services and had come to appreciate the value of having colleagues all over the country . . . and the fruits of experience under nationalization were being put to good account."
Well! Well! It would appear that after all his prolonged bombardment of the Ivory Tower, its wing was demolished with some careful marking of stones with a view towards re-erection elsewhere.
Although it was understood that the main excuse for destruction was the need for competition, the penance of Janus (April 5 and 12) appears to be to encourage the smaller competitors in their groping—through a rigmarole of cautious probing, into addresses for returi loads, codes of conduct, definitions and directories of long-distance hauliers, revised registers "of each kind '' and "joint organizations . . that are likely to work smoothly . . ."—towards inter-working.
Meantime, while some humble users sadly watch the passing of personal contact and control, and others wryly recall their past ability to refer to one comprehensive national directory, the issue of additional coded lists relating to conditions of carriage and adequacy of insurance cover is considered more important by at least the writer.
Nottingham. INTERESTED CUSTOMER.
Careless Talk Costs Loads
IT cannot be impressed too much upon drivers that it A is unadvisable to talk of journeys, goods carried and so on in public places so that one's conversation can be overheard. Neither is it prudent to be drawn into conversation with strangers except on the weather and other matters not relating to haulage.
The ramifications of some of the gangs stealing goods from lorries have reached a stage when something drastic must be done to reduce the appalling yearly losses. Obviously the police will be intensifying their efforts in the coming Months, as will everybody connected with the road haulage industry. There is, however, something which we can all do—keep a quiet tongue in our heads. Even the odd and apparently innocent words dropped here and there about time, route, cargoes and so on, can be picked up and pieced together by the " intelligence " men who make up part of the thieves' gangs.
A recent report puts last year's figure of goods stolen from lorries at Elm. and, to date, £300,000 this year. This must stop. Every exhortation should be given to drivers, mates and others by wall posters, sticker labels in offices, mess-rooms and vehicle cabs to "Watch Out" and remember that careless talk can result in the loss of a valuable consignment of goods.
Southend-on-Sea. " TRUNKIE,"