IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Henry Percy Holt and Francis William
Crossley at the Office of the Commissioners of Patents on the 20th July 1882.
HENRY PERCY HOLT and FRANCIS WILLIAM CROSSLEY both of Gt Marlbro St
Manchester in the County of Lancaster, Engineers "IMPROVEMENTS IN GAS
MOTOR ENGINES"
Our invention relates to a construction and arrangement of gas motor engine and
method of working it in such a manner that during each revolution of the crank
shaft products of combustion are discharged from the cylinder, and a partial vacuum
being formed therein a charge of combustible gaseous mixture is admitted, this
charge along with the residuary products in the cylinder is compressed and being
ignited propels the piston. For this purpose the inlet and outlet ports of the
cylinder with their slides or valves are so arranged as to provide for the cycle of
operation as follows: When the piston is about half way in its outward stroke the
discharge port is opened and a considerable portion of the products of combustion
escape, the port is then closed and the piston continues its stroke creating a partial
vacuum in the cylinder behind it. While the piston is near the end of its outstroke
the inlet port is opened and combustible mixture enters the partially vacuous space
in the cylinder. The piston afterwards beginning its return stroke the inlet port is
closed and the piston makes its instroke compressing the contents of the cylinder,
but in order to prevent too great a proportion of incombustible diluent being thus
retained a portion of this is permitted to escape through the exhaust port during
the earlier part of the return stroke, care being taken, by providing diaphragms on
the back of the piston or in the cylinder itself, that the combustible portion of the
charge shall be retained. When the piston reaches the end of its instroke the
compressed combustible charge is ignited and the piston is propelled outwards,
whereupon the cycle of operation is repeated. The opening and closing of the ports
as above described may be effected by valves or slides worked by eccentrics or cams
on the engine shaft. We prefer however to adopt a more simple arrangement by
making the piston itself or a plate attached to it as it moves over the ports at the
side of the cylinder successively uncover and cover them in the required order.
Ignition may be effected by any known means.
For the purpose of governing the engine we adopt an arrangement which is

page_text: applicable generally to gas motor engines in which, in case of excessive speed,
retardation is effected by suppressing entirely the supply of gas during one stroke
or several strokes. At the end of a lever worked by a centrifugal governor, which
may be very small, we form a long boss in which is fitted a rod free to slide, this
rod having a head from which projects backwards a die or piece of metal with a V
On the main slide of the engine which
shaped groove formed in its end.
reciprocates we fix a blade in such a position that when the engine is moving at
normal speed this blade encounters the groove of the die above mentioned. When
however, owing to excess of speed, the governor causes the lever with the sliding
rod and die to rise, the blade on the slide misses the die. The head of the sliding
rod faces a head on the stem of the gas supply valve which is usually kept closed by
a spring. When the engine is working at normal speed, the blade on the slide
encountering the die near the end of the stroke of the slide pushes the sliding rod
against the stem of the gas supply valve causing the valve to open and admit gas
to the working cylinder. When however owing to excessive speed of the engine
the blade on the slide misses the die, there is no supply of gas given until the speed
becomes sufficiently reduced to permit the die again to take such a position as to be
encountered by the blade on the slide. From the stem of the supply valve we work
by a pawl and ratchet wheel a spindle carrying wires that dip into an oil cup and
as they move transfer drops of oil or lubricant to tubes supplying oil passages in
the slide and cylinder. As this lubricating arrangement is worked by the
movement of the gas valve, the supply of lubricant is given only in proportion
approximately to the demand for it, that is to say according as more or less gas is
consumed in the engine, so more or less lubricant is supplied.