Ford Turbine Rivals Oil Engine in Economy
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FUEL economy rivalling that of an oil engine of comparable horse-power, and superior to that of a petrol engine under most operational conditions, is claimed for a 300 s.h.p. gas-turbine engine for vehicle applications c'eveloped by the Ford Motor Co., Dearborn, Michigan.
A spokesman for the British Ford company told The Commercial Motor that there was no immediate prospect of the engine being introduced here.
Whereas most previous gas-turbine designs for installation in vehicles have used single-stage air compression, the Ford engine, designated the 704, has a two-stage compression layout combined with dual combustion chambers.
This results in maximum fuel economy being achieved throughout the range of 25-100 per cent. of 6.111 power in comparison with earlier designs, which reached maximum efficiency only at or near their maximum output.
The specific fuel consumption is stated to be 0.56 lb. fuelfb.h.p./hr. at full power, 0.48 lb./b.h.p./hr. at half-power, and 0.58 lb./b.h.p.ihr. at quarter-power. The last figure in particular is a great improvement on consumption rates already obtained with engines of this . type.
Complete with all accessories, the . engine weighs 650 lb., when installed against the 2700 lb. of a typical American oil engine of equivalent power. It is approximately 3 ft. 2 in. long, 2 ft. 5 in. wide and 2 ft. 4 in. high, and could fit easily into the engine compartment of the current American Ford truck, normally occupied by a V8 petrol engine.
It can be run on a variety of fuels, including unleaded petrol, paraffin, aviation gas-turbine fuel or light diesel oil. As with other gas turbines, an advantage is that no warming-up period is required after starting.
Low-speed Rotor
In operation, air is drawn into the first compression stage, which is a relatively low-speed rotor turning at 46,500 r.p.m. Assuming an ambient temperature of 100° F., this stage, which exerts a 4-to-1 compression, raises the air temperature to 450° F. and at full power passes 2.7 lb. of air per second. The second compressor, which operates at 91,500 r.p.m., raises the air temperature to _625° F. After passing through an exhaust-gas heat-exchanger, the air, haying now reached 1,000° F., is fed into the first combustion chamber.
Fuel is then sprayed into the chamber and combustion takes place. The resulting gas is used to drive the turbine for the high-speed compressor, after which it passes into the second combustion chamber, where more fuel is added.
The gas is then passed through the power turbine, driving it at 36,000 r.p.m., and the two turbine wheels that drive the low-speed compressor. After traversing the heat exchanger they exhaust to air at a temperature of 740° F., which is approximately similar to the temperature of the exhaust gases of a conventional petrol engine fitted in a car.
A30 Step-down gearing between the powerturbine shaft and the transmission propeller shaft of the vehicle in which it is fitted reduces the speed of this member to 4,600 r.p.m. at full power.
In addition to its obvious use in lorries and buses, Ford envisage the 704 as a power unit for armoured fighting vehicles, earth-moving equipment and light locomotives.
Although the degree of exhaust silencing obtained is not mentioned, the low temperature of the exhaust gas and the obvious efficiency of the heat exchanger suggest that there should be little noise.
UNSEEN WEIGHT: MIDLAND CASE DISMISSED COMPLAINTS were made by a
defence solicitor at West Bromwich magistrates court last week about methods adopted by a Birmingham Corporation Inspector of Weights and Measures.
A lorry driver, Harold Richards, 9 Mill Street, West Bromwich, and his employers, Samuel Whitehouse and Sons, Ltd., King Street, West Bromwich, were charged under the Weights and Measures Act, 1936, with transporting sand in a lorry which was not marked with the correct tare weight. The employers were summoned for causing the offence.
Mr. Alexander Daniel, a Birmingham Inspector of Weights and Measures, said that the tare weight was recorded on the chassis as 2 tons 18 cwt., but a check revealed it to be 3 tons 1 cwt. 3 qrs. Mr. D. Morgan, defending, complained that instead of summoning a member of the company to the public weighbridge to settle the matter, Mr. Daniel made the driver wait outside the office and did not give him the opportunity to see the weighing. He was not given a ticket to prove the weight.
A prosecution witness, Mr, A, Dixon, West Bromwich chief inspector of Weights and Measures, agreed with Mr. Morgan in cross-examination that in the circumstances -he would have taken the driver into the office to witness the weighing.
The magistrates dismissed the charges, but Richards admitted five other offences of having incorrect conveyance notes, five cases of failing to sign the notes and one case of unloading sand without delivering a note. He was fined a total of £16 with costs.