15 Subjects in M.I.R.A. Future Programme
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Research on 12 Other Problems Already in Progress, Including Fuel Injection in Spark-ignition Engines
AS reported in "The Commercial Motor" last week, the Motor Industry Research Association has overcome its early financial difficulties and is now engaged in an energetic programme. Twelve subjects are at present under review and IS are included in the schedule for the future.
Research in progress is concerned with filtration of lubricating oil; wear of journals with copper-lead bearings; failure of gears by surface fatigue, tooth breakage and scuffing; fatigue strength of cast crankshafts; deepdrawing properties of sheet metals; cylinder-head and exhaust-valve temperatures; operation of engines on leaded fuel; piston-ring flutter; design and positioning of piston rings; fuel injection in spark-ignition engines; stresses in vehicle structures under road conditions, stiffness of vehicle structures, and application of electrical methods of measuresnent.
Full Programme Work scheduled for the immediate future has been curtailed because of lack of facilities, but still comprises the following comprehensive list:—Equipment for noise measurement; noise of oil engines; exhaust and intake silencing; gear noise; body noise; wind noise; wear and boundary friction; rustproofing; octane number requirements; cetane number. requirements; fuel quality and performance; volumetric efficiency; brakes; back-axle gears; and body panels.
According to the annual report of M.I.R.A., the Association's plans, and particularly the future location of the laboratory, are largely bound up with the proposal to .establish a proving ground. A report by a sub-committee of M.I.R.A. on this question was presented last May to the Society of Motor Manufacturers and Traders, and the industry's verdict is still awaited. The technical side of the industry is said to be generally in favour of setting up a proving ground an a disused aerodrome.
The immediate purpose of research into stresses in vehicle structures is to develop portable equipment for measuring them under road conditions and to discover the ways in which the plant can most usefully be employed. Tests are being made on a large car and a lorry.
Stiffness tests are being carried out on chassis frames and complete assemblies of frames and bodies, to arrive at the hest method of determining torsional stiffness.
Efforts are being made to determine the requirements of a satisfactory filter for engine lubricating oil and to formulate a method of test by which the performance of oil filters may be assessed. The wear caused by solid impurities on typical engine components is being measured. A report is in preparation dealing thoroughly with the performance ol magnesium-alloy materials intended for use as connecting-rod big-end bearings.
Work on gears, during the past year, has been largely concerned with the influence of the lubricant on loadcarrying capacity. All the [lendingfatigue testing machines have been occupied with cast crankshafts, and two reports are being prepared* Results so far obtained in another set of tests show that mixture strength is the principal factor influencing exhaust-valve temperature and that, if this be maintained constant, only the quantity of heat (or fuel) passed through the engine exerts a significant influence.
Petrol Injection
Research into fuel infection in sparkignition engines is being conducted at London University under the super
vision of Prof. E. Giffen. Experimental work has been concerned with the study of the atomization of intermittent fuel sprays produced by using low-viscosity, fuel at low injection pressure with a centrifugal single-orifice open nozzle.
In the immediate future, the effect of nozzle dimensions is to be deter, mined, and the spray produced by this type of nozzle is to be compared with that from a poppet-valve closed nozzle. Apparatus has also been constructed for examining the coefficient of discharge of different types of nozzle and the flow of fuel through them.