Improvements in Gas and Petroleum Engines.
Year: 1891

page_text: Date of Application, 24th Dec., 1891-Accepted, 6th Feb., 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by PIERRE FERNAND FOREST and GEORGES
GALLICE, of No. 6, Boulevard de Strasbourg, Paris, in the Republic of
France, Engineers.]
Improvements in Gas and Petroleum Engines.
I, HENRY HARINGTON LEIGH, Assoc. M. Inst. C.E., Fel. Ch. Inst. P.A.,
practising as Phillips and Leigh of No. 22, Southampton Buildings, Chancery
Lane, in the County of Middlesex, Engineer and Patent Agent do hereby declare
the nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:—
This invention relates to improvements in gas and petroleum engines and its
object is to provide for the complete utilization of the gaseous products of
combustion before they are expelled from the cylinder.
The indicator-diagrams taken on engines made according to the present inven-
tion shew that the exhaust has a pressure varying between three and four
atmospheres. This represents a considerable loss of energy, due firstly to the
pressure not used and secondly to the power used to expel the exhaust.
To remedy this drawback it would be necessary to make the stroke of the
piston long enough to allow the gases to expand to atmospheric pressure. But it
would also be necessary for the charge of gas and air to remain in the cylinder the
same time. Now if the piston stroke is lengthened the volume of the charge is
increased accordingly and the final result will be exactly the same.
What is required therefore is to be able to increase the piston-stroke during the
expansion period, keeping it the same as before during the charging and com-
pression periods, or what comes to the same thing to reduce the stroke during the
charging period, keeping it the same as before, during the expansion period, or in a
word to reduce the charge, keeping the other matters as before.
This being arranged for and it being borne in mind that in 4 cylinder engines
one of the pistons always begin to draw in a charge while another of them begins
to compress, this invention in its widest sense relates to the returning into the
former cylinder a portion of the compressed charge.
The accompanying drawings illustrate one application of the invention to a
4 cylinder-engine of the Pilon-type.
Fig. 1 is a side elevation of the upper portion of a 4 cylinder engine. The
latter and the valve chests are in section so that the circulation may be traced
more conveniently.
Fig. 2 is an elevation corresponding therewith.
The base of the engine is not affected by our invention, consequently it is
omitted from the figures.
A, A', A', A' are the four cylinders and a, a¹, a³, a³, are the respective supply
valves. B is the supply-main.
C, C, C, C³, are levers having their fulcra upon axes D supported on the
engine in any convenient way. They are arranged in such a way that one of their
ends shall have just been lifted just off the respective feed valve spindle, whilst the
other end (which carries an anti-friction roller) is in contact with a cam adapted to
regulate their action as it is required. These cams are mounted upon the shaft E,
which also actuates the exhaust valves and the igniting contacts.
This Specification describes the application of the invention to a reversing Pilon
engine with electric ignition, but it is to be distinctly understood that this is only
one example, and that the said invention is equally applicable to any type of
4 cylinder engine.

page_text: The invention acts in the following manner :-
The cylinder A having finished its feeding stroke and the cylinder A' beginning
its stroke, the lever C operated by the respective cam swings on its fulcrum and
presses upon the spindle of the valve a which it keeps open for a determinate time.
During this latter the return stroke of the piston drives the charge past the
valve into the pipe B, whence it is drawn into the cylinder A'. This latter in
its turn sends a portion of its contents into the cylinder A¹ which in its turn
delivers into the cylinder A³ and so on.
a,
The volume returned is adjusted so that the exhaust shall be at atmospheric
pressure.
The construction above described is equally adapted for the purpose of utilizing
the exhaust in slowspeed engines. In fact with such engines the exhaust takes
place at half-stroke, with a corresponding loss. Now according to this invention
the energy lost is instead led into the next cylinder and a corresponding economy
effected.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In 4 cylinder engines delivering a portion of the inflammable charge into a
cylinder then making its charging stroke.
2. The combination of devices adapted to effect the delivery of a portion of the
inflammable charge as described with reference to the accompanying figures.
Dated this 24th day of December 1891.
HENRY H. LEIGH.