Novelty in Engine-starting Mechanism T'
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E are many reaSons why
manual effort, as a means for starting large internal-combustion engines, is undesirable. A source of power for this purpose is compressed air and a very interesting form of equipment for its employment is offered in the HeywoodJ.A.P. high-pressure injection starter. It is handled, so far as the motor trade is concerned, by the Equipment and Engineering Co., Ltd., 2 and 3, Norfolk Street, Strand, London, W.0.2. This interesting machine not only rotates the crankshaft, but supplies a carburettecl mixture to each cylinder.
Two main components comprise the installation on a chassis; on the engine is the compressor-distributor unit, whilst the reservoir or air bottle is conveniently mounted on the vehicle. Interest primarily concerns the former component, which weighs about 25 lb. and measures only 8 ins. by 6 ins.
Drive for the two-stage air-cooled compressor unit is taken from the camshaft or from any other shaft which can be arranged to give half crankshift speed. Bolted to the compressor is a distributor-valve unit, whilst a petrol container forms the closed end of the casing. The valve takes the form of a disc with two ports in it ; one allows a large volume of air, at a
pressure of 400 lb. per sq. in., to pass to each cylinder on its firing stroke; the other port allows a small quantity of
carburetted mixtare of petrol and air to be injected into each cylinder just before the occurrence of the spark, Enough air is in the reservoir for
several -starts. On the outlet end of the air bottle is mounted the automatic relief valve, which prevents the pressure exceeding 400 lb. per sq. in. This assembly comprises several valves of special design, which, it is claimed, will hold pressure indefinitely and need no maintenance. The starting valve is operated by a remote control, which is normally mounted upon the dashboard.
The air compressor is in action all the time the engine is running, but the relief valve prevents storage of air at any pressure above 400 lb. per sq. in. Should the starter control be operated while the engine is running, or in case of a backfire, the engine or starter will suffer no harm. Mixture cannot be forced into any cylinder on its power stroke unless the engine be revolving.
Hitherto the Heywood-J.A.P. starter has principally been used for aircraft engines. If preferred, a distributor could be mounted on each engine in a fleet and a cylinder on a trolley coupled to the distributor of the engine to be started. The workshop compressor would provide the required air pressure for charging purposes.