Motor Engines.
Year: 1887

page_text: Date of Application, 15th Mar., 1887
Complete Left, 15th Dec., 1887
Complete Accepted, 20th Jan., 1888
Motor Engines.
I SAMUEL GRIFFIN of Kingston Iron Works, Bath, in the County of Somerset,
Engineer do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in gas motor engines, for the purpose of
obtaining greater expansion of the explosive compound after ignition, before its release
from the motor cylinder, and consequently increased economy.
In gas motor engines as hitherto constructed it has been usual to introduce into the
motor cylinder, a charge of explosive compound, equal to the cubical contents of the
sweep of the piston, in addition to the compound contained in the compression space,
such compression space being usually proportioned to the volume of the sweep of the
motor piston, so that when the whole contents of both motor cylinder and compression,
or clearance space, are compressed before ignition, a pressure considerably above that
of the atmosphere is obtained. Such compressed explosive compound after being
ignited, and expanding in the motor cylinder, usually released at a pressure of from
30 lbs. to 40 lbs. above the atmosphere, thus entailing a considerable loss of available
power.
According to my present improvements I propose to remedy these defects by
employing a motor cylinder with the charging and exhaust ports arranged in accordance
with or similar to that described in the Specification of Letters Patent granted to me
dated 23rd August 1883 No. 4080 and contained in the fourth claim i.e. the charge
is introduced through a port situated at a point close to, or near the piston when ai
its full in" or compressing stroke, while the exhaust port is situated at the extreme
end of the compression space, furthest from the piston, the charging and exhaust

page_text: ports are consequently at opposite ends of the compression space. I make the
compression space according to my present improvements, of a cubical content con-
siderably less in proportion to the cubical contents of the sweep of the motor piston,
than has hitherto been usual; such cubical content being determined by the desired
amount of expansion of the explosive compound in the motor cylinder. The cycle
employed may advantageously be either that described in the Specification of
Letters Patent before referred to No. 4080 1883 or what is known as the
double cycle. Other methods of introducing the explosive charge into the motor
cylinder may also be employed without departing from the nature of my
invention.
In carrying out my invention in connection with the double cycle, the operations
will be as follows:-During the whole or any suitable portion, of one outstroke of the
piston, air and gas, or explosive compound, is drawn into the motor cylinder immediately
behind the piston, through the charging port before described, the air or products of
combustion contained in the compression space remaining practically undisturbed in a
mass, and consequently unmixed with it. During the first portion of the next instroke
the exhaust valve is open for a sufficient time to allow the whole, or any required
portion of the before mentioned air, or products of combustion contained in the
cylinder or compression space, to be driven out; the exhaust valve is now closed, the
remaining portion of the instroke compressing the combustible or explosive charge
into the compression space; at about the beginning of the next outstroke the charge is
fired, and expanded during the remaining portion of the stroke. At the next
instroke the exhaust valve is opened and a portion of the products of combustion,
equal to the sweep of the piston is expelled, leaving only that contained in the
compression space.
The entire cycle is now completed.
In carrying out my present improvements in connection with my improvements in
gas motor engines described in the Specification of Letters Patent before referred to
No. 4080-1883 the operation will be as follows :-
During one outstroke of the piston air will be drawn into the cylinder and gas may
also be admitted during the first part of this stroke if desired at the next instroke the
exhaust valve is open, and a portion of the air (acting as a scavenging or cleansing
charge) will pass through the exhaust valve, carrying with it the products of combus-
tion or air previously contained in the compression space. During the whole, or any
suitable portion of the next outstroke, air and gas, or explosive compound, is drawn
into the cylinder. During the first portion of the next instroke, the exhaust valve is
again open for a sufficient time to allow the whole, or any required portion of the air
contained in the compression spaco and cylinder (in front of the explosive charge) to
be driven out. The exhaust valve is now closed, the remaining portion of the stroke
compressing the charge. At about the commencement of the next outstroke the
charge is ignited, and expanded during the remaining portion of the stroke. During
the next instroke a portion of the products of combustion equal to the sweep of the
piston, is expelled, leaving only that contained in the clearance or compression space.
The cycle is now completed. The above cycle is applicable either to the single acting
or double acting engines described in the Specification of my Letters Patent No. 4080
of 1883 before referred to.
In cases where great expansion of the ignited charge in the motor cylinder is desired
(and consequently a comparatively small compression or clearance space containing a
proportionately small volume of combustible mixture, in relation to the volume of the
entire sweep of the motor piston is used). It will be necessary to admit the combustible
charge only during a portion of the charging stroke (as before described). Under
these conditions it may be advantageous to open the exhaust valve at about the same
time as the combustible charge is cut out of the charging stroke, so that during the
remaining portion of this stroke, pure air, or the products of combustion contained in
the exhaust pipe may pass through the exhaust passage into the compression or
clearance space in front of the combustible charge which is next the piston. The
exhaust valve remaining open during the first portion of the next instroke until a

page_text: sufficient portion of the air or products of combustion contained in the compression
space is ejected as before described.
It will be obvious that any desired amount of expansion practicable of the ignited
combustible charge in the motor cylinder may be obtained by varying the amount of
explosive compound drawn into the motor cylinder immediately behind the piston,
together with the cubical content of the clearance or compression space and the
proportion of the compressing stroke, during which the exhaust valve is allowed to
remain open.
Dated this 15th day of March 1887
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Arrangement and Construction of Gas
Motor Engines.
I SAMUEL GRIFFIN of Kingston Iron Works, Bath, in the County of Somerset,
Engineer 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 :-
My invention relates to improvements in gas motor engines, for the purpose of
obtaining greater expansion of the explosive compound after ignition, before its
release from the motor cylinder, and consequently increased economy.
In gas motor engines as hitherto constructed it has been usual to introduce into the
motor cylinder a charge of explosive compound, equal to the cubical contents of the
sweep of the piston in addition to the compound contained in the compression space,
such compression space being usually proportioned to the volume of the sweep of the
motor piston, so that when the whole contents of both motor cylinder and compression
or clearance space are compressed before ignition, a pressure considerably above that
of the atmosphere is obtained. Such compressed explosive compound after being
ignited and expanding in the motor cylinder is usually released at a pressure of from
30 lbs. to 40 lbs. above the atmosphere, thus entailing a considerable loss of available
power.
According to one part of my present improvements I propose to remedy these
defects by employing a motor cylinder with the charging and exhaust ports arranged
in accordance with or similar to that described in the Specification of Letters Patent

page_text: granted to me dated 23rd August 1883, No. 4,080, and contained in the fourth claim.
i.e. the charge is introduced through a port situated at a point close to or near the
piston when at its full "in" or compressing stroke, while the exhaust port is situated
at the extreme end of the compression space furthest from the piston, the charging
and exhaust ports are consequently at opposite ends of the compression space. I
make the compression space according to my present improvements, of a cubical
content considerably less in proportion to the cubical contents of the sweep of the
motor piston than has hitherto been usual, such cubical content being determined by
the desired amount of expansion of the explosive compound in the motor cylinder
after ignition. The cycle employed may advantageously be either that described in
the Specification of Letters Patent before referred to No. 4080, 1883, or what is known
as the double cycle. Other methods of introducing the explosive charge into the
motor cylinder may also be employed without departing from the nature of my
present invention, as hereinafter described.
In carrying out my invention in connection with the double cycle the operations
will be as follows: During the whole or any suitable portion of one outstroke of the
piston, air and gas, or explosive compound, is drawn into the motor cylinder
immediately behind the piston through the charging port before described, the air or
products of combustion contained in the compression space remaining practically
undisturbed in a mass, and consequently unmixed with it,
During the first portion of the next instroke the exhaust valve is open for a
sufficient time to allow the whole or any required portion of the before mentioned air
or products of combustion contained in the cylinder or compression space to be driven
out; the exhaust valve is now closed, the remaining portion of the instroke
compressing the combustible or explosive charge into the compression space.
At about the beginning of the next outstroke the charge is fired and expanded
during the remaining portion of the stroke. At the next instroke the exhaust valve
is opened and a portion of the products of combustion equal to the sweep of the
piston is expelled, leaving only that contained in the compression space.
The entire cycle is now completed.
22
According to another arrangement the combustible charge may be introduced into
the cylinder through a port in its back end, in a similar manner to that employed in
the ordinary double cycle engine or for instance the "Otto Engine. At any
suitable point during the first "out" or charging stroke of the piston the entering
charge of combustible compound is cut off by means of any suitably arranged valve.
During the remaining portion of this stroke the charge already contained in the
cylinder will expand forming a partial vacuum. During the first portion of the next
instroke of the piston the pressure of the atmosphere against the piston will tend to
restore the energy already absorbed in forming the before mentioned partial vacuum.
When the piston has reached the position at which equilibrium is restored between
the atmosphere and the charge contained in the cylinder, compression of the charge
will commence and continue until the completion of the stroke. The charge is now
ignited at about the commencement of the next out stroke of the piston and expanded
throughout the entire or any suitable portion of the stroke doing work upon the
piston. At the next instroke of the piston a portion of the products of combustion
are expelled through the exhaust valve, the cycle being now completed.
It will be obvious that the expansion of the ignited charge may be varied by
altering the point in the stroke of the piston at which the entering charge is cut off.
The size of the compression space may also be varied in accordance therewith so as
to produce any required degree of compression previous to ignition.
This latter arrangement may also be applied to Motors in which the charging and
exhaust ports are arranged in accordance with my said Patent No. 4,080 and
described in this Specification.
In carrying out my present improvements in connection with my improvements in
gas motor engines described in the Specification of Letters Patent before referred
to No. 4,080-1883 the operation will be as follows :-
During one outstroke of the piston air will be drawn into the cylinder and gas may

page_text: also be admitted during the first part of this stroke if desired at the next instroke
the exhaust valve is open, and a portion of the air (acting as a scavenging or cleansing
charge) will pass through the exhaust valve, carrying with it the products of com-
bustion or air previously contained in the compression space. During the whole, or
any suitable portion of the next outstroke, air and gas or explosive compound is drawn
into the cylinder. During the first portion of the next instroke the exhaust valve is
again open for a sufficient time to allow the whole or any required portion of the air
contained in the compression space and cylinder (in front of the explosive charge)
to be driven out. The exhaust valve is now closed, the remaining portion of the
stroke compressing the charge. At about the commencement of the next outstroke
the charge is ignited and expanded during the remaining portion of the stroke.
During the next instroke a portion of the products of combustion equal to the sweep
of the piston is expelled, leaving only that contained in the clearance or compression
space. The cycle
now completed. The above cycle is applicable either to the
single acting or double acting engines described in the Specification of my Letters
Patent No. 4,080 of 1883 before referred to.
In cases where great expansion of the ignited charge in the motor cylinder is
desired (and consequently a comparatively small compression or clearance space
containing a proportionately small volume of combustible mixture in relation to the
volume of the entire sweep of the motor piston is used,) it will be necessary to admit
the combustible charge only during a portion of the charging stroke, as before
described. Under these conditions it may be advantageous to open the exhaust valve
at about the same time as the combustible charge is cut out of the charging stroke,
so that during the remaining portion of this stroke, pure air, or the products of com-
bustion contained in the exhaust pipe may pass through the exhaust passage into the
compression or clearance space in front of the combustible charge which is next
the piston, the exhaust valve remaining open during the first portion of the next
instroke until a sufficient portion of the air or products of combustion contained in
the compression space is ejected as before described.
It will be obvious that any desired amount of expansion practicable of the ignited
combustible charge in the motor cylinder may be obtained by varying the amount of
explosive compound drawn into the motor cylinder together with the cubical content
of the clearance or compression space and the proportion of the compressing stroke
during which the exhaust valve is allowed to remain open.
DESCRIPTION OF DRAWINGS.
Figures 1. 2. 3 and 4 (Sheet 1) show sectional plans of Gas Motor Cylinders with
admission and exhaust valves attached arranged in accordance with my improvements
for obtaining greater expansion of the ignited charge in double cycle engines in which
the charging and exhaust ports are arranged in a similar position to that shown in my
Specification No. 4,08083 and described in the first portion of my present Specification.
The same letters of reference indicate the same parts in all the drawings. a motor
cylinder 6 piston, showing portion of a connecting rod attached, c exhaust valve,
d admission valve, e admission port into cylinder, fadmission port in valve, g admission
port through cover through which port either air or air and gas can pass the
admission of the gas being controlled by a valve not shown, h igniting port in valve,
valve cover.
The piston is intended to communicate motion to a crank or other suitable device,
in any convenient manner, the admission and exhaust valves being actuated in the
usual way by means of cranks cams or other suitable mechanism.
::
out
Figure 1 shows the piston and valves in position at the commencement of the first
or charging stroke. Figure 2 shows the same parts in their relative positions
at the moment of cutting off the entering charge of combustible compound before the
entire stroke is completed. Figure 3 shows the same parts in their relative positions
at that point in the next "in" or compressing stroke at which the exhaust valve
(having allowed all necessary products of combustion or air to be driven out) is about

page_text: to close the remaining portion of the stroke of the piston compressing the charge.
Figure 4 shows the same parts in their relative positions at the end of the compressing
stroke previous to the ignition of the combustible charge.
The mode of operation is as follows:-
At the commencement of the first outstroke of the piston Figure 1 the admission
valved which is travelling in the same direction as the piston, is about to open
communication between the port g in the cover and the port e in the cylinder by
means of the port so that the combustible compound can pass into the cylinder
immediately behind the piston, the exhaust valve c being closed. During the time
the piston is moving into the position shown in Figure 2 (this position being varied
according to the required amount of expansion of the ignited charge) the admission
valve will have travelled forward fully opening communication between the ports g,f, e,
and returned again to the position shown in the figure at which point it is about to
cut off communication and thus prevent further entrance of any combustible com-
pound during the remaining portion of the stroke of the piston. At this point the
exhaust valve c commences to open allowing pure air or products of combustion to
pass into the cylinder behind the combustible compound until the stroke of the piston
is completed the exhaust valve c remaining open until the piston has reached the
position in its next instroke shown in Figure 3 (this position being varied according
to the required amount of the ignited charge) the air or products of combustion
admitted behind the combustible charge during the previous outstroke being thus
wholly or partially expelled. At this point the exhaust valve rapidly closes, the
admission valve being in the position shown in this figure. The combustible compound
is now compressed, during the remaining portion of the instroke of the piston until it
reaches the position shown in Figure 4, at this point the admission valve has by its
movement established communication between the ignition port and the compressed
combustible compound in the cylinder through the port e. The combustible com-
pound is now ignited and expands doing work upon the piston during its entire (or
any convenient portion of its) next outstoke. During the next instroke of the
piston the exhaust valve is open and the burnt gases partially expelled, the cycle being
now completed.
Figures 5. 6. 7. 8 show sectional plans of gas motor cylinders with admission and
exhaust valves attached and arranged in accordance with or in a similar way to those
of the ordinary "Otto,” or double cycle engine and described in the second part of my
final specification.
Figure 5 shows the piston and valves in position at the commencement of the first
"out
or charging stroke. Figure 6 shows the same parts in their relative positions
at the moment of cutting off the entering charge of combustible compound before
the entire stroke is completed. Figure 7 shows the relative positions of the same
parts during the next instroke at the moment when equilibrium of pressure is estab-
lished between the combustible compound in the cylinder and the atmosphere
compression of the charge by the piston immediately commencing. Figure 8 shows
the same parts in their relative positions at the end of the compressing stroke previous
to the ignition of the combustibles charge.
The mode of operation is as follows :-
At the commencement of the first outstoke Figure 5, the admission valve d is about
to open communication between the port g in the cover i and the port e in the cylinder
by me: ns of the port so that the combustible compound can pass into the compression
space and mix with the air or products of combustion already contained therein the
exhaust valve c being closed. During the time the piston is moving into the position
shown in Figure 6 (this position being varied according to the required amount of
expansion of the ignited gases) the admission valve & will have travelled forward fully
opening communication between the ports g. f. c. and returned again to the position
shown in the figure at which point it is about to cut off communication and thus
prevent the further entrance of any combustible compound into the cylinder during
the remai ing portion of the stroke of the piston the exhaust valve being closed, the
combustib, e compound will become attenuated and a partial vacuum be consequently

page_text: formed behind the piston until its stroke is completed. From the commencement of
the next instroke of the piston until it has reached the position shown in Figure 7
(which position corresponds with that shown in Figure 6 at which the supply of com-
bustible compound is cut off) the atmosphere will do work upon the piston tending to
restore equilibrium of pressure in consequence of the partial vacuum in the cylinder.
At this point (the combustible compound being at atmospheric pressure) the piston
will commence the compression of the charge which will continue until the end of its
stroke shown in Figure 8 the charge is now ignited, by means of the ignition port
which has been brought into position by the movement of the valve, and expands
during the whole or any convenient portion of the next outstroke doing work upon
the piston. During the next instroke of the piston the exhaust valve is open and the
burnt gases partially expelled. The cycle being now completed.
Figures 9. 10. 11. 12. 13. 14 show sectional plans of gas motor cylinders with
admission and exhaust valves attached. The cycle and position of charging and
exhaust ports being in accordance with my Specification No. 4,08033.
Figure 9 shows the position of piston and valves at the commencement of the first
"out" or air charging stroke of the piston. Figure 10 shows the same parts in their
relative positions at the commencement of the following instroke. Figure 11 shows
the same parts in their relative positions at the end of the instroke during which tho
products of combustion together with air, have been expelled through the exhaust
valve. Figure 12 shows the same parts in their relative positions during the next
outstroke at the moment of cutting off the entering charge of combustible com-
pound before the entire stroke is completed, the exhaust valve at the same time
opening and allowing pure air or products of combustion to pass into the cylinder
behind the combustible compound until the end of the stroke. Figure 13 shows the
same parts in their relative positions at the point in the next " in
stroke at which the exhaust valve (having allowed all necessary air to be expelled) is
or compressing
about to close, the remaining portion of the stroke of the piston compressing the
charge. Figure 14 shows the same parts in their relative positions at the end of the
compressing stroke previous to ignition.
The mode of operation is as follows:-
At the commencement of the first "out" or air charging stroke Figure 9 the
admission valve d is about to open communication between the port g in the cover i
and the port e in the cylinder by means of the port f so that air can pass into the
cylinder during the entire stroke of the piston when this stroke is complete as shown
in Figure 10. all communication through the ports g.f. e. will be cut off by the
forward movement of the admission valve d and the exhaust valve will commence
opening during the whole of the next instroke the exhaust valve will remain open, so
that all products of combustion together with a portion of the air contained in the
cylinder will be expelled through the exhaust valve leaving only that contained in the
compression space the exhaust valve now closes, while communication between
the ports g. f. e. is again about to open by means of the return movement of the
admission valve d as shown in Figure 11. During the first portion of the next out-
stroke air and gas or combustible compound is admitted into the cylinder through the
ports g. f. e until the piston has reached the position shown in Figure 12. (this position
being varied according to the required amount of expansion of the ignited charge).
At this point the entering charge is cut off by the movement of the admission valve d
and the exhaust valve opens so that during the remaining portion of the stroke, air,
or products of combustion can pass through the exhaust passage into the cylinder
behind the combustible charge, during a portion of the next instroke, the whole or a
portion of the air or products of combustion which previously entered through the
exhaust passage are again expelled through the exhaust valve, which remains open
until the piston has reached the position shown in Figure 13 (this position being
varied according to the required amount of expansion of the ignited charge). At
this point the exhaust valve closes, the remaining portion of the stroke of the piston
compressing the combustible chargo. At the commencement of the next outstroke
the admission valve will have moved into the position shown in Figure 14, the charge

page_text: being ignited by means of the igniting port h will expand doing work upon the piston
during the whole or any portion of the stroke during the next instroke of the
piston the exhaust valve is open and the burnt gases partially expelled, the cycle being
now completed.
I would have it clearly understood that I do not limit myself to the exact details
described nor do I limit myself to Gas Engines, using the particular cycles described
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. The improved method of introducing a combustible or explosive charge into the
motor cylinder of a Gas Motor Engine during a portion only of one stroke of the
piston followed by air or products of combustion during the remaining portion of the
same stroke the whole or a portion of the air or products of combustion being again
expelled in order that the volume of the combustible charge contained in the cylinder
before compression may be less than the volume of the combustible charge when
fully expanded in the cylinder after ignition.
2. The improved method of introducing a combustible or explosive charge into
the motor cylinder of a Gas Motor Engine during a portion only of one stroke of the
piston the remaining portion of the same stroke being completed without the further
admission of any gas air or products of combustion a partial vacuum being thus
formed behind the piston in order that the volume of the combustible charge contained
in the cylinder before compression may be less than the volume of the combustible
charge when fully expanded in the cylinder after ignition.
3. I claim the introduction of a charge of combustible or explosive compound into
the motor cylinder of a Gas Motor Engine during a portion only of the full stroke of
the piston the entering charge being cut off before the stroke is completed substantially
in the manner and for the purposes hereinbefore set forth.
Dated this 15th day of December 1887