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"Smoothing" the Oil Engine

4th July 1947, Page 35
4th July 1947
Page 35
Page 36
Page 35, 4th July 1947 — "Smoothing" the Oil Engine
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ELIMINAT1ON of a substantial proportion of the noise and vibration that is customarily associated with the oil engine is the object of a flexible mounting designed by the Gardner organization. This system was the subject of Patent No. 483,703 by L. Gardner and Sons, Ltd., Patricroft, Manchester, about 10 years ago, and it is now being put into full use, having been adopted as standard by certain manufacturers.

The system consists of either two or three-point mounting, the usual arrangement being the latter. The layout can provide one point at the front and two at the rear, as was originally visualized. Alternatively, as in the more recent product, there can be a single mounting at the rear (consisting of a Silentbloc unit in the crankcase end-plate), with two spring cup units mounted on the crankcase side-facings at the forward end of the engine.

These cup units each consist of a cylinder containing a spring to support the weight of the engine, with highrate rubber buffers to limit the stroke upwards and downwards. The weight of the engine is suspended from a pair of bolts which pass through the spring cups and are held in them by the coil springs located between the rubber end buffers.

Adjustment of the spring cups is such that the engine is permitted to oscillate freely about its natural axis, that is to say, the axis about which it has the minimum movement of inertia, but the amplitude of oscillation in the vertical plane is controlled within defined limits by the rubber buffers. These buffers provide an abutment to resist torque reaction and to prevent excessive movement of the engine in consequence of road shocks.

The object of providing freedom for certain movement about the natural axis is to absorb as completely as possible the compression reaction forces developed at idling speeds by dissipating them in overcoming the inertia of the moving mass of the engine.

Under conditions of both light running and load, the mounting is claimed completely to insulate the chassis from high-frequency vibration, Thus, if provision be made to prevent the direct transfer of engine noise through the bulkhead by means of some suitable form of soundproofing, reasonable silence can be obtained in the passenger compartment, as the noises from the engine are not regenerated by vibration of the body panels.

Although it is float mounted, the unit is fitted to the frame in the same manner as if solidly attached.

When inspecting this device, the writer was able to take part in a brief test of a Lagonda car in which a Gardner four-cylindered engine was thus mounted. In this instance, there was notable freedom from either vibration or noise, it being practically impossible to tell that there had been any change from the normal power unit fitted to this vehicle. (It should be emphasized in this connection that for the present, Gardner engines are not normally available for fitting to private cars.) As it would appear likely that the effects would be even more pronounced when fitted to a public service vehicle. the probability is that the system will materially raise the prestige of the oil engine with both drivers and passengers of coaches and buses fitted with the latest Gardner engine.

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Organisations: Gardner
Locations: Manchester

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