New Fuel Meter Gives More Power
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With Less Petrol
IGHTEEN months ago, Mr. W. D.
Marchant, better known in the world, of motorcycling than in the commercial-vehicle field, called on The Commercial Motor" with a graph showing the performance of a petrol engine fitted with a special metering device. Compared with the curves obtained with an engine fitted with a normal carburetter, those recording the performance with the Marchant meter were impressively Quperior.
Controlled Fuel Flow Mr, Marchant was at that time conducting experiments and development work with the Thornycroft concern at Basingstoke, and last week the first public announcement was made of the existence of his invention. In its function the device resembles a carburetter, in that the pressure of the fuel is controlled by engine suction, but the main feature lies in the control of fuel flow, which is pre-determined and constant throughout the complete speed range of the engine. In other words, the fitting provides the means for controlling the quantity of fuel and the period when it is allowed to enter the inlet manifold. • The regulator which is employed is conveniently driven off the end of the dynamo, if this be gear driven, the speed of the regulator being the same as that of the engine. It provides a cam to operate the valve controlling the maintenance of 'the pressure period round the jet nozzle. This controls the flow of fuel from the jet for approximately 30 per cent. of the inlet-valve opening period, the flow period being limited to the centre of the suction curve.
A governor mechanism, incorporated in the regulator assembly, operates a double throttle on the apparatus attached to the inlet manifold. This throttle movement is related to engine speed, and serves to maintain a depression in the inlet manifold to control a constant degree of atomization.
Correct Mixture Maintained Interconnected to these throttles is a taper-needle valve which proportions the air-fuel ratio and maintains the correct mixture strength. The speed of a vehicle powered by an engine fitted with this device is controlled by means of the usual accelerator pedal.
Claims made for the fitment are smoother running, increased power output, and improved torque at low engine speed, The overall reduction in fuel consumption is stated to be as high as 33f per cent. under the most favourable conditions; the increase in power is said to be up to 10 per cent.
• One of the main reasons for these claimed improvements is that a far better distribution of the mixture is obtained over a normal type of induction system with a single carburetter, and further, by controlling the pressure period round the jet when the inlet valve is open, there would be a marked improvement at part-throttle opening positions.
A specimen power curve shows Opt, whereas at 1,800 r.p.m. a Thornyeroft 3.8-litre engine gave approximately 55 b.h.p., the same unit, with the Marchant metering device, produced 62 b.h.p. at 1,800 r.p.m. Torque, b.m.e.p., and fuel-consumption figures all show a marked improvement.
The sole licensee for the BrackhouseMarehant fuel-metering device is J. Brockhouse and Co., Ltd., West Bromwich, Staffs.
Whilst it will be some considerable time before the device becomes available, it is understood that the first models to be produced will be for commercial vehicles.
U.K. REPRESENTED AT PARIS CONGRESS OF I.R.T.U, QN Tuesday the Paris Congkess of the International Road Transport Union opened. Col. A. Jerrett, Minst.T., and Mr. F. D. Fitz-Gerald, F.C.1.S., president and secretary respectively of the Traders' Road Transport Association, and Mr. B. G. Turner, chairman of the Road Haulage Association, represent Britain.
Daily sessions of the Congress continue until to-day, and to-morrow there will be an official reception, which will be attended by the president of the Paris Municipal Council. During the week delegates attended a special session of the French National Transport Federation.
The I.R.T.U. has been accorded recognition by the United Nations as an organization to be consulted by.United Nations working parties set up to study international aspects of transport.