overgenomen uit The Engineer, 1890.
The small petroleum motor illustrated here, is designed for the modern requirement for a small easily-started motor. The size illustrated here is about one-sixth horse power; sufficient for most of those requirements which, although below the power of one man, are too fatiguing for continuous hand or foot work.
The engine has been made under the patent of Mr Edward Butler, in the works of Mr F.B. Shuttleworth at Erith, where a much larger size of engine is being made for launch work, and a different form for driving a tricycle. The little engine is very readily and easily started, and the electric ignition seems to introduce no difficulty.
The illustration is a perspective view, showing the engine in front of the small tank containing cooling water for the jacket. In the front are seen the pitch-chain wheel, which is fixed to the end of the nearly cylindrical valve, by means of which the charge of petroleum vapour and air is admitted. The small handle, which controls a throttle valve for starting and stopping, is also seen in this view.
The bottom section of the engine casting forms a petroleum well, with a float valve. It is connected by a 1/16 in. pipe to a half-gallon supply can, which holds the petroleum for a day's working. Over the well is placed an atomiser, into which petroleum is induced to flow up, by the suction caused by the flow of air drawn through a nozzle arrangement, by the motor piston. The petroleum feed is regulated by means of an indexed valve.
The mixture of air and petroleum spray formed in this atomiser is further volatilised in a chamber and then distributed to the cylinder by the rotative valve metioned above. This valve is provided with a pair of inlet and exhaust ports. The inlet ports communicate with the volatilisation chamber; and the exhaust ports with the exhaust pipe.
The piston works in the four-stroke compression cycle, and the valve rotates once for every two complete revolutions; it is kept up to its seat by a spring. The speed is controlled by a throttle valve connected to the hand lever, seen in the perspective view. The ignition is effected by the passage of sparks between two terminals carried in an insulator. The current for this apparatus is induced in a coil placed in connection with a small special bichromate battery. The sparks are timed at the right periods, by means of contact plates on a communicator, at the back of the valve-chain wheel. When not using the motor for more than an hour at a time, an ordinary bell battery is said to supply sufficient current.
Overheating of the valve and cylinder is prevented by water circulation through the jacket. The water is fed by pipe from a tank containing about five gallons.
The cylinder and body are in one casting. The piston is connected to a rocker arm by a short connecting rod. The rocker arm pivots in lugs on the frame of the engine. A second short connecting rod couples the rocker arm with the crank. This peculiar construction causes a somewhat quicker outstroke than return stroke, which is advantageous; besides rendering the motor very compact.
The crank has 1 5/16 in. radius. The size of the cylinder is 2 in. diameter by 3 7/8 in. stroke, and the revolutions are variable from 250 to as much as 800 per minute. The total height of the motor is 16 1/2 in.; width of base, 7 in. by 12 in. over the lugs; and the weight, without water tank, 110lb.