Expendable Oil Engines
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ALTHOment of oil engines was UGH the develop originally mainly undertaken for marine and industrial purposes, the advanced design of the modern unit can be largely credited to the makers of types for commercial vehicles.
" Unlike the designers of petrol engines, those engaged on oil-engine research have benefited little from the progress made with aircraft power units and high-performance models for record-breaking and racing, in the production of which cost has often been a secondary consideration.
Nevertheless, the road-vehicle oil engine probably represents the most successful attempt in the history of internal-combustion to match performance to the requirements of an exacting user at the minimum cost. If it had been developed to satisfy only private-car owners and, consequently, mass produced, it would almost certainly have been an inferior article, judged by present-day standards.
It is pertinent, however, to review the effect that such a development might have on the design and production of commercial-vehicle units if it were initiated in the near future. That the possibility exists must be regarded seriously.
The obvious advantages to the commercialvehicle operator would be the reduced cost of oilengined chassis for lightweight vehicles and the gradual improvement in servicing facilities at Aayside garages throughout the country.
Better Facilities Overseas?
Of importance to the manufacturer Would be the extension of facilities in many districts overseas where mechanics now have little knowledge of oil-engine repairs or lack the necessary equipment. The scarcity of oil-fuel supplies in such areas would also be redressed. If there were a large price differential in this country between oil fuel and petrol, such as exists in Germany, the greater gain in fuel economy would influence private-car owners to be far less fastidious regarding any slow-running roughness, Diesel knock and reduced performance. With a relatively small differential, smooth running and performance must be improved, and the first-cost reduced, before sales resistance can be broken down and a sufficiently large market assured to warrant the very high expenditure on capital equipment which would be necessary for quantity production. It would also be necessary for the unit to be suitable as an alter. native to a petrol engine and therefore to have similar output, torque and speed characteristics.
Although the extra cost of the complete vehicle which the motorist would. be willing to pay, would, in part, depend upon the saving in fuel costs, he would be less influenced by the prospect of a gain over the years, in place of a substantial price reduction, than the average commercialvehicle user. It might, for example, be expedient to fit comparatively inefficient injector equipment with a low first cost than a high-precision type giving improved economy.
Sacrifices for Production?
Apart from advances that may be made in the strictly technical sense, acceptable characteristics might be obtained by a sacrifice in durability. It can reasonably be assumed that the average motorist would be satisfied with half the mileage between engine overhauls or replacements than is now demanded by the operator of an oilengined vehicle. This would give the designer greater latitude. and enable production to be simplified.
The unit envisaged would be expendable in the way that the low-cost petrol engine is now considered expendable compared with an oil engine. Moreover, its higher power output would not necessitate heavier transmission components, because the maximum torque developed would be lower. Its lightness would obviate chassis strengthening and the use of heavier suspension components.
A unit of this type would be immediately acceptable to those users who replace vehicles at short intervals after running a limited mileage A29 because the use of up-to-date models is beneficial to their business. To the operator of passenger and goods vehicles covering much greater mileages, to whom a modern appearance is of relatively little value, the car unit would have little appeal unless the service offered by the manufacturers and their distributors enabled his repair staff to be drastically reduced or dispensed with. Many fleet operators now employ petrol-engined vehicles because the replacing of engines and other major components can be performed between routine runs, and this eliminates the need for a. spare vehicle.
Those who own high-quality cars might be the last to purchase models fitted with oil engines, but a minority demand would stimulate the production of engines with an output equal to that required to power heavy passenger and goods vehicles. The easily replaceable low-cost oil engine might also, therefore, be applied at a later date to these classes of vehicles if competition between car manufacturers reduced production costs.
There are many records of existing types of oll engine propelling a vehicle for 400,000 miles or more before attention to the crankshaft assembly has been required. Reliable operation for less than 100,000 miles might, however, be acceptable to the users if the engine could be replaced overnight for a fraction of the former cost.