Note: Descriptions are shown in the official language in which they were submitted.
to ~ !~ f~
WO 90/15917 ~'~ ~ '~'' v tl PCT/AU90/00261
1.
RECIPROCATING PISTON ENGINE WITH PUMPING AND POWER CYLINDERS
TECHNICAL FIELD
This invention relates to reciprocating piston internal
combustion engines of the type wherein) pumping and power
cylinders are operated on two stroke cycles.
BACKGROUND ART
Engines of this type have been disclosed in numerous prior
/oart which have intended to improve the efficiency and or power
to weight ratio thereof. US,A) PATENT NO 1,881,582 shows a
design which has a pumping cylinder driven at twice the cyclic
speed of and alternately suppling a intake scavenging charge to
two power cylinders, via transfer parts which communicate with
the lower cylinder walls of the power cylinders, hence being
timed by the power pistons. Although this design marginally
increases the scavenging efficiency attainable and as compared
to crankcase compression type two stroke engines, this design
has and retains numerous efficiency problems of) including the
lo~undamental inefficiency of, the conventional two stroke
engine. The said inefficiency results from the opening of the
transfer ports in the lower cylinder walls and which reduces
the volume through which expansion occurs with the said
reduction being used instead for a half of the transfer
scavenging phase. Furthermore this design, due to the said
transfer to the lower cylinder walls, has no potential for
significant efficiency gains to be attained if' valve controlled
constant volume combustion chambers are to be used.
A second type of engine which has pumping and power
3ocylinders operating on two stroke cycles and which have
intended to overcome the above said undesireable features are
typically disclosed in U S PAT NO'S . 3,880,126 and 4,458,635.
These designs have the pumping cylinder transferring the intake
charge through valve timed ports which open into the power
cylinder head section. U S PAT NO : 3,880,126) utilizes a
combustion chamber which is in constant communication with the
power cylinder and which has an excessive number of components
whilst overall efficiency and power output are Beverley limited
by a poor scavenging efficiency which primarily results from
_ 2060203
.e long transfer scavengi g phase required of the design. This
further exacerbats the obvious power to weight ratio
limitations of the design. U S PAT NO: 4,458,635) utilizes a
valve controlled constant volume combustion chamber which
S foregoing the supercharging system used that results in a
similar said fundamental inefficiency) increases the scavenging
and combustion efficiency and hence overall efficiency is also
maginally increased. Subsequently, only an average power to
weight ratio results whilst an excessive number of components
/O. i s st i 11 a mad or problem.
A further design of engine which shares similiar cylinder)
port and valve locations of the presented invention but .yrhich .-
is outside of the technical field of this invention in that the .
power cylinders operate on four stroke cycles, is typically
/S,shown i.n GB,A PATENT NO 2C?1210. As such the pumping cylinder
is used only as a supercharging device and is not necessary for
the operation of the engine as is required in~the presented '
invention.
It is therefore an object of the present invention to
provide a novel two stroke internal combustion engine.
DISCLOSURE OF THE INVENTION
The present invention discloses a novel engine design
which significantly increases the thermal efficiency and
power to weight ratio of the types of engines discussed above.
The present engine design also increases the scavenging
efficiency of the above types of engines while decreasing the
number of components required for the second type of prior
art engines discussed above.
According to the present invention there is provided
a two stroke internal combustion engine comprising
at least one unit having a pumping cylinder, a pumping piston
reciprocably movable in said pumping cylinder, two power
cylinders, a respective power piston reciprocably movable in
each said power cylinder, each said power cylinder having an
associated combustion chamber, the pumping piston
reciprocating at a cycle speed twice that of the power pistons w
and said power pistons being phased about one stroke apart,.-a
20b0203
cylinder head closing off ends of all said cylinders, said
head having two transfer ports therethrough enabling said
pumping cylinder to communicate with said power cylinders,
transfer valves controlling communication between the pumping
cylinder and the power cylinders, at least two exhaust ports
through said head allowing exhaust gases to flow from the
power cylinders, exhaust valves controlling the flow of the
exhaust gases, at least one intake port through the head and
communicating with the pumping cylinder, intake valve means
associated with the intake port and allowing a major portion
of intake charge to be induced into the pumping cylinder when
the pumping piston is moving away from its top dead centre
position and said pumping piston alternately transferring the
charge into the power cylinders through the transfer ports as
the pumping piston moves towards its top dead centre position,
said pumping piston leads to the top dead centre position the
power piston of the power cylinder to which the charge is
transferred, the transfer valves begin to open at a -time ......__..
between 20% to 80% of the cycle time taken for the pumping
piston to move through a cycle from the top dead centre
position and close at a time between 20% before and after the
cycle time taken for the pumping piston to move from the top
dead centre position, the exhaust valves opening when the
associated said power piston is at about or before its bottom
dead centre position. '
CA 02060203 1999-06-16
- 3a -
Preferably, the pumping piston of a said unit is
equally distanced to the power cylinders thereof and leads
the piston of the power cylinder which the intake charge is
to be or is being transferred into, to the 'top dead centre'
(from hereinafter referred to as 'TDC') position, by less
than 80% of the time required for a power piston decreasing
volume stroke. A separate mainshaft mechanism to that which
causes reciprocation of the power pistons, causes reciproca-
tion of the pumping piston, and the pump mainshaft is driven
by means, from the power mainshaft or the output shaft of
the engine.
It is further preferred that the abovesaid engine is
operated in a manner wherein the said transfer and exhaust
valves of the power cylinders open and close in the same or
a similar timed relation to the movement of the piston of
the respective power cylinders. The said induction of said
intake charge occurs substantially on the increasing volume
stroke of the pumping piston, and the said induced intake
charge is then
-- ~~~~'~A~r 9 0 / J Q 2 6 ~
RECEIVED 2 2 ApR 1991
20b0203
4
transferred to a said. power cylinder, substantially on the
decreasing volume stroke of the pumping piston. After
combustion occurs when the piston of a respective power
cylinder is about its TDc; position, the said power pistons are
,S'.forced to move through to BDC with exhaust occuring when the
respective exhaust valves open, which is after the.respective
power piston has_moved through atleast 45 % of its down stroke.
A said exhaust valve then remains open for atleast 35 % of the
time required for a power piston stroke, and atleast
/0 substantially) untill the respective transfer valve opens to
allow for atleast partial scavenging of the remaining volume of
the said power cylinder. Substantially atleast over the said
engine operating load and speed range, as a said intake charge
is transferred to a power cylinder) the pumping cylinder
/.~ performs atleast a part of the work required to raise the
pressure of the intake charge, to a pressure which is suitable
far combustion. The said valves which enclose a said combustion
chamber volume and including atleast the said transfer valves)
close before 30 %.of the combustible mass is combusted) and
2o.substantially atleast close before combustion occurs. Preferred
valve timings which allow for the efficient operation of the
said engine in the abovesaid method are also stated.
A further object of this invention has the engine just
described being optionally modified by various improvements
lSthereto and which have; the said transfer ports being the only
ports where air is administered to the power cylinders, and
being located higher than the reversal point of the piston top;
the pumping cylinder mainshaft being located directly above the
power cylinder mainshaft; the valve train actuating means and
3~ or other auxilary device) being driven from means provided on
or being located on the pumping cylinder mainshaft or) on the
power cylinder mainshaft between the said power cylinders and
which provides for a compact engine and unit to be achieved;
.;
desirable combustion chamber designs of both abovesaid
3S.combustion chamber types with the transfer and secondary valves
being poppet type valves and with desirable locations and
timings thereof. A still further object of this invention has
enviable V configurations and turbocharged designs of the navel
engine whilst a further object has the pumping cylinder
SUBSTITUTE S~rIEET
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utilising crankcase compression thereof to improve the charging
efficiency thereof. A variable valve timing mechanism which
varies atleast the closing time of the exhaust valve so that
its closing time may be varied to allow efficient operation
Sunder transient operating conditions is yet another abject.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG 1- is a top schematic view of the preferred design
which is a inline single unit and showing the cylinders) ports,
combustion chamber and valve opening locations thereof.
/O. FIG 2- is a cross sectional view taken along line A-A of FIG
. 1 but around the piston crankshaft mechanism and with the lower
crankcase removed.
FIG 3- is a valve timing diagram of the preferred design in
power cylinder crank angle degrees with the lines indicating
~S.valve open times and with the TDC position shown thereon being
the TDC position of the first power piston.
; FIG 4- Sliows an alternative design which has two units,
;
being in a V configuration and utilizing turbocharging and
'a crankcase compression of the pumping cylinder. One unit or bank
Zc.of cylinders is shown as a end view with the other unit shown
- as a cross sectional view taken along line B-B of FIG 5 but
:.r
around the piston crankshaft mechanism thereof and with partial
hidden detail shown and the lower power crankcase and lower RH
side pumping cylinder crankcase being removed.
2S. FIG 5- is a top schematic view of the sectioned unit of FIG
4 and shows the cylinders, ports, combustion chambers and valve
opening locations thereof.
FIG 6- is a valve timing diagram of the alternative design
shown in FIGS 4 and 5 and uses the same features as described
30. for FIG 3.
FIG 9- is a end shematic view of an alternative V
,~:; configuration and which shows the cylinder and crankshaft
locations thereof.
MODES FOR CARYING OUT THE INVENTION
~3 S. Refering to all modes for carrying out the present
invention, each said unit has a pumping cylinder 5 with a
pumping piston 16 reciprocable therein and first and second
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power cylinders, respectively 3 and 4 with first and second
power pistons respectively 13 and 14 reeiprocable within their
respective power cylindErs. All cylinders of a unit share a
parallel axis and a common block 18 and a common head 19)
S whilst the pumping cylinder is evenly distanced to each of the
power cylinders.A pumping crankshaft 2 and pumping conrod 17
cause reciprocation of the pumping piston 16 and a power
crankshaft 1 and power conrods 15 cause reciprocation of the
said power pistons. Each said crankshaft is supported for
/O.rotation by bearing means whilst journal means which are not
shown in the drawings, provide pivotal movement at the conrod
crankshaft pivots and the conrod piston pivot. A pump drive
gear ? which is fixed to each of the pumping crankshafts 2)
cooperates with) is driven by, and is one half the diameter of)
/S, the power crankshaft gear 6 which is fixed to the power
crankshaft 1. This gear arrangement then provides far the
pumping pistons 16 to be reciprocated at and cyclicly operated
at) twice that of the power pistons. The phasing of the power
pistons of a unit relative to each other, is one hundred and
ZO.eighty power 'crankshaft crankangle'<from hereinafter is
refered to as 'GA'> degrees. The first and second transfer
ports respectively 21 and 24) remain in constant communication
with the pumping cylinder. The crankshafts for carrying out all
modes of the invention, are of the one piece type whilst all
ZSconrods are of the two piece type and bolt on to the respective
crankshafts from the undersides thereof, for pivotal movement
therearound. Of course the components and auxiliaries not
illustrated and refered to) and which are required for the
efficient operation of the engine) are included in all modes
3o.for carrying out the invention whilst water cooling passages
are shown in the sectioned walls of FIGS 2 and 4 but are not
numbered to reduce cluttering thereof. Furthermore) the
respective components of the first and second power cylinders
,a
are respectively refered to as the first and second said
3S. components, or they are refered to as the respective components
' of the power cylinder of which the description is directed to.
Refering now to FIGS 1-3, the preferred design or mode for
carrying out the invention, is a naturally aspirated inline
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2060203 ~'~'~'! ~~ 4 ~ ; ~~. ~ ~ v
RECEIVED - 5~'d 199
7
version which has the pumping cylinder 5 at all load and speed
operating conditions, performing a part of the work to raise
the pressure of the combustible mixture within the power
cylinders) to that which is used far combustion, and is located
S.in the middle of the first and second power cylinders)
respectively 3 and 4. The pumping crankshaft 2 is accessed and
heI3-in place by pumping crankshaft caps 38 which bolt into the
engine block 18 whilst the power crankshaft 1 is accessed and
held in place by the lower crankcase which is removed in the
~O.FIG 2. The phasing of the pumping piston 16 relative to the
power pistons 13 and 14 has the pumping piston leading the
piston of the power cylinder which the intake charge of that
particular pumping cylinder cycle will be transfered into) to
TDC) by forty power CA degrees.
The preferred design has all intake) transfer) and exhaust
valves being poppet type valves. The first and second combustion
chambers respectively 22 and 25, remain in constant
communication with their respective power cylinder and each has
a spark plug 35 mounted thereinto and which causes ignition of
20.the combustible mixture therein. Petrol fuel injection means 36
are mounted into each transfer port and inject a predetermined
quantity of fuel thereinto as the said intake charge is being
transferred into the power cylinder thereof. A first transfer
valve 8 times communication between the first transfer port 21
2 S and the first power cylinder 3 whilst a second transfer valve
times communication between the second transfer port 24 and
the second power cylinder 4. Two intake valves 12 time
communication between the intake port 20 and the pumping . '
i
cylinder 5. A first exhaust valve 9 times communication between
3othe first power cylinder 3 and the first exhaust port 23 whilst
a second exhaust valve 11 times communication between the
second power cylinder 4 and the second exhaust port 26. The said
exhaust ports lead to an exhaust manifold and eventually to an
exhaust pipe whilst the said intake port leads to an intake
35,manifold with air metering means therein provided. All of the
said valves are actuated by a single overhead camshaft which
has a axis parallel to that of the crankshafts and is
positioned directly above all the said valves so as to directly
actuate them. The said camshaft is not shown on FIG 2 to reduce
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2060203 '~~''' ~
g. RECEIVED - 9 (VGV 1990
cluttering thereof and of the major features therof. The said
camshaft is driven by chain means 46 from the camshaft drive
sprocket 39 which is fixed to the pumping crankshaft 2. The
sprocket on the said camshaft which cooperates with the said
-s. chain is a half of the diameter as the said camshaft drive
gear, providing for the said camshaft to operate at the same
cyclic speed as the power cylinders and as such) single
camlobes actuate the transfer and exhaust valves) whilst two
camlobes are evenly spaced around the said camshaft where the
/4 intake valves are actuated from, so that the intake valves open
twice as often as the other valves and which follows the
increased cyclic speed of the pumping cylinder. Variable
exhaust valve closing event is obtained by a turning block type
of variable valve timing mechanism which is not shown for
/S. reasons of undue complexity and which allows for the said
valves to close between fifty and sevsnty power CA degrees
before TDC and depending on engine load and speed. This said
variable closing is shown on FIG 3 by the dashed line thereon.
The engine oil pump supplies the oil to the engine and is
i
20.driven from the oil pump drive gear 40 which is fixed to the
power crankshaft 1 between the power cylinders.
The method of operation including the valve timings of the
preferred design is now described. The intake valves I2 open
when the pumping piston moves through to sixty pumping CA
2S,degrees after TDC. This allows the compressed intake gas of the
-- previous cycle to expand substantially to atmospheric before
the said valves 12 are opened. With the intake valves 12 opened
and the pumping piston moving towards its 'bottom dead centre' '
<which from hereinafter is refered to as 'BDC') position) the
3ointake air is induced into the pumping cylinders. As the said
piston 16 moves through forty said CA degrees after BDG the
intake valves 12 are closed and the induction of the intake air
ceases. At the same time the intake valves 12 close) one of the
-_
transfer valves 21 or 24 begins to open, initiating the
35transfer phase to the respective power cylinder of which the
said open transfer valve opens into. The said transfer valve
then remains open untill the pumping piston l8 moves through to
ten said CA degrees after TDC which is shown in FIG 3 and being
thirty five power CA degrees before the piston of the said
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2060203'
9. REC~ivEa - ~ ~~~:~ ~a9o
respective power cylinder reaches TDC. The piston oz the
pumping cylinder then continues towards BDC, and begins a new
cycle thereof as is described above and when the intake valves
12 begin to open again at sixty pumping CA degrees after TDC.
S.The intake air of the ne:ft said cycle is transfered to the
other power cylinder and the intake air of the following said
cycle-and which is after the said next cycle is transfered to
the said respective power cylinder starting a new cycle
thereof.
/0 During the first part of the transfer phase to the said
respective power cylinder) the exhaust valve thereof is open,
providing for the later part of the exhaust phase thereof to
occur which has the scavenging of the remaining exhaust gases
from the said respective cylinder by the transfering intake
/S. air. The exhaust valve of the said respective power cylinder
remains open untill the piston thereof moves to between fifty
and seventy power CA degrees before TDC. At high load and or
high speed) the fuel is injected into the transfer port of the
said respective power cylinder during the transfer phase and at
20.1ow load and or speed, it is mostly infected after the exhaust
valve of that power cylinder has closed. With the fuel
injected) a spark at the respective spark plug 35 causes
i combustion to occur about the TDC position. The piston of the
said respective power cylinder then moves towards BDC,
' 1S substantially expanding the gases therein to atmospheric before
the exhaust valve begins to open when the said piston is at
forty five power CA degres before BDC. This then initiates the
first part of the exhaust phase being blowdown) and then
positive scavenging, occurs whilst the piston thereof moves
i
3o. towards TDC untill the transfer valve of that cylinder opens,
. beginning another cycle thereof and as is described above. The
operation of the other power cylinder is the same as that
described above for the said respective power cylinder but as
is obvious) it occurs one hundred and eighty power CA degrees
3S.before and after it occurs in the said respective cylinder.
Refering now to FIGS 4-6) the alternative design or mode for
. carrying out the invention has two units which are set in a V
configuration and with each said unit being one bank of
' , cylinders of the said V. The~power cylinders of each unit) are
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ID. ~~(~0205 RECEI~icp _ ~ ~10V ;990
positioned close together with the pumping cylinder 5 of each
unit being positioned on the outside of the said.V but being
central to the power cylinders of its said unit. Constant
volume combustion chambers which have communication to their
.S.respective power cylinders being timed by secondary valves are
used in the alternative design with the first said secondary
valve being 27 and the second said secondary valve being 28. A
turbocharger 41 is positioned in the middle of the said V with
the exhaust manifolds 23 of all power cylinders communicating
/o) thereto whilst the exhaust ) ports 2;3 and manif olds '?3 share the
same reference number. The pressurised intake manifold 42
leading from the turbocharger 41 communicates with the intake
ports of bath pumping cylinders whilst the crankcase intake
ports 33 of both pumping cylinders is naturally aspirated. A
lS,single power crankshaft 1 causes reciprocation of all power
pistons whilst each pumping cylinder 5 has its own pumping
crankshaft 2. A single power crankshaft gear 6 which is fixed
to the power crankshaft, cooperates with the pumping cylinder
drive gears 7, fixed to each of the pumping crankshafts. The
ZOphasing of the pumping pistons relative to the power cylinders
of a respective unit, has the pumping piston leading the said
power pistons to TDC by fifty power CA degrees. The pumping
cylinder performs all the mechanical work to raise the pressure
of the intake air from the pressure obtained within the pumping
2S.cylinder) to the pressure obtained in the combustion chambers
due to compression. The phasing of the power pistons of the
unsectioned unit relative to the said pistons of the sectioned
t
unit, has the first power piston 3 of the sectioned unit,
leading the said first power piston of the unsectioned unit) by
3aninety power CA degrees. The power crankshaft l is accessed and
held in place by the lower power crankcase which is removed in
the drawings whilst each pumping crankshaft 2 is accessed and
held in place by a pumping lower crankcase 4? which is shown on
the unsectioned unit of FIG 4.
3s. The alternative design has all intake, transfer) exhaust and
secondary valves being poppet type valves whilst the crankcase
intake valves 32 are reed type valves. The first combustion
chamber 22 and the first power cylinder 3 has communication
therebetween controlled by a first secondary valve 27 whilst
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the second combustion chamber 25 and the second power cylinder
4 have com.-nunication therebetween controlled by a second
secondary valve 28. viesel fuel injection means 37 are mounted
into each said combustion chamber whilst ignition therein is
S.caused by the temperature and pressure of the combustible
mixture therein. Protrusions 31) on the top of each power
pi~bn, extend upwards so that they substantially atleast) take
up the volumes of each secondary port 29 and 30 which result in
an efficiency increase of the engine. The alternative design
/o. has each unit having the same intake, transfer, and exhaust
valve and port arrangements and functions) as are described for
the preferred design although the positioning of some valves
and ports is altered. Each said unit has two overhead camshafts
which are not shown in the drawings and which are driven by
/,S gear means from the pumping cylinder drive gear 7. One of two
r
idler gears 43 cooperates with the said gear ? whilst the
u
: another idler gear 44 cooperates with the idler gear 43 and
with the camshaft gear 45 which is the same diameter as the
power crankshaft gear 6. The said Camshaft gear 45 is fixed to
24.the power camshaft which has single camlobes actuating each
secondary, and exhaust valves whilst another gear
transfer
)
which is fixed to the said power camshaft cooperates with a
P'
gear which is a half the diameter thereof and which is fixed to
the pumping camshaft. The said pumping camshaft has single
camlobes actuating the intake valves with the said diameter
2S
,
difference of the relevant gears providing for the increased
cyclic velocity of the intake valves.
The method of operation including the valve timings of, the '
.i
alternative mode is now described with reference to a single
3o. unit. The intake valves 12 begin to open when the pumping
~
Y
piston~moves through to seventy pumping CA degrees after TDC.
This allows the compressed intake air from the previous cycle
to expand substantially to the-pressure of the intake manifold
before it opens. With the intake valves I2 opened and the
.i
.3S pumping piston moving towards its BDC position) the intake air
~' is induced into the pumping cylinder 5. Whilst the said piston
16 is moving towards BDC) the intake air within the_crankcase
is compressed. If the engine is operating above or about, fifty
percent of its possible load, then the turbocharger 41 is
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1
2060203 RECEIVED - 5 ~OV 1990
operating efficiently, and as the pumping piston uncovers the
crankcase transfer ports 34 at fifty said CA decrees before
BDC) then no crankcase transfer occurs as the pressure in the
said cylinder resulting from the turbocharger 41 is as high or
S. higher than that of the said crankcase. This then provides for
j the said crankcase compression to be utilized at the lower
lows but not at the higher loads as well as minimizing the
maximum pressures attained in the said crankcase which then
reduces the sealing requirment thereof and allowing for lighter
/O said reed valve materials with lower opening pressures. As the
said piston 16 moves through to fifty said CA degrees after
BDC) the crankcase transfer ports 34 are closed and when the
said piston moves to sixty said CA degrees after BDC, the
intake valves 12 are closed and the induction of the intake air
~S through the intake ports ceases whilst if the engine is
operating at a low load then on the said pistons up stroke)
- intake air will be induced into the crankcase through the
crankcase intake valves 32. One of the transfer valves opens
when the pumping piston i.s at its BDC positon, to initiate the
ZO,transfer phase to the respective power cylinder which the said
transfer valve opens into. The said transfer valve then remains
open untill the pumping piston has moved to ten said CA degrees
after TDC and which is the same as that shown in FIG 6 and
being forty five power CA degrees before the piston of the said
2S.respective power cylinder reaches TDC. The piston of the
pumping cylinder then continues towards BDC and begins a new
cycle thereof when the intake valves begin to open again at
seventy pumping CA degrees after TDC .whilst the intake air of '
the next said cycle is transferred to the other power cylinder
3o. and so forth as is described hereinbefore.
During the first part of the transfer phase to the
respective power cylinder) the secondary valve thereof is open
providing for the scavenging of the exhaust gases from the
combustion chamber thereof. The said secondary valve closes
3S when the piston of that respective power cylinder has moved to
one hundred and fifteen power CA degrees before TDC. During
this time the exhaust valve of the said respective power
cyliader is open and closes when the piston thereof has moved
. to forty five power CA degrees before TDC) allowing for nearly
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2060203 v v ~'.~ a ~ ;' ~ ~ ~ ~~
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all the exhaust gas to be scavenged from the said cylinder
except for a small residual portion thereof remaining. This is
retained to highly pressurise the remaining gas so that when
the secondary valve reopens when the piston thereof is at five
$.pawer CA degrees before TDC) the pressure in the power cylinder
is not significantly lower than that of the combustion chamber
thereof which would decrease the thermal efficiency attainable.
When the said piston is positioned about forty power CA degrees
before TDC) diesel type fuel is injected into the said
/o. combustion chamber which results in combustion occuring just
' after the said relevant transfer valve has closed and so that
' as the said secondary valve thereof is opened) about fifty
percent or more of the combustible mass has been combusted.
With combustion completed and the said power piston moving
lS.towards BDC, the gas from the combustion chamber flows through
the secondary port and open valve thereof to expand
.' substantially to atmosperic before the exhaust valve of the
said cylinder is opened when the piston thereof is at forty
power CA degrees before BDC. This initiates the exhaust phase
2oof the said cylinder and as the piston thereof moves towards
' TDC) it positively scavenges the paid cylinder untill the next
transfer phase thereinto begins which starts the next cycle
thereof and as is described above. The operation of the other
power cylinder has the same said valve and cyclic operation as
ZS.that described above for the said respective power cylimder but
as is obvious) it occurs 180 power CA degrees before and after
it occurs in the said respective cylinder.
The alternative V configuration of FIG ? has two units being
inthe said configuration with each said unit being one bank of
:i
.3o.cylinders for the said engine whilst the pumping cylinders 5
i thereof~are located to the inside of the said V) and of the
power cylinders. A single pumping crankshaft 2 causes
reciprocation of both said pumping pistons 16 whilst a single
power crankshaft 1 causes reciprocation of all said power
3S. cylinders.
Obviously) many modifications and variations of the present
invention are possible and it is therefore understood that
within the scope of the appended claims) the invention may be
. practised otherwise than as specifically described.
_ _ ......~.-----
~~5'i3s~ i ~T1~'~~ S:'~EE
