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Патент USA US2127165

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Aug. 16, 1938.
2,127,165
J. J. EHRAT
DIESEL ENGINE
2 Sheets-Sheet l
Filed Oct. 19. 1936
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33
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54
VC'OMPEESSELD GAS
4s
18 25:;
OR, INJECTION AÍR. LINE,
FUEL LINE.
53
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1A.
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'75
35'72 à
l*
FU ELPUMPWITH
DELIVERY VALVE'.
REMOVED
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Gttornegs
Aug, 16, 1938.v
-.J_ J. l-:HRAT
2,127,165
DIESEL ENGINE
Filed oct. 19..19se
Bu
2 Sheets-Sheet 2
KM@ dm
Gttomegs
Patented Aug. 16, 1938
iiNiTE
2,127,165
STATES
ATENT OFFICE
2,127,165
DIESEL ENGINE
.lîean J; Ehrat, Milwaukee,v Wis., assignor to
Nordberg Manufacturing Company, Milwau
kee, Wis., a corporation of Wisconsin
Application October 19, 1936, serial No. 106,442
7 Claims. (c1. 12s-s3)
This invention relat es to Diesel engines and
particularly to means for controlling fuel injec
tion.
While the invention has utility in connection5 with air injection en gines of the type in which
it is desirable to vary the lift of the air injec
tion needle valve, it is intended chiefly for use
with engines operatin g according to the methods
described and claime d in the patents to Nordberg,
10
No. 1,857,256, May 10, 1932, and No. 1,962,282,
June 12, 1934. A mech anical control for such en
gines is described and claimed in Patent No.
1,949,577, March 6, 1934.
Generally stated , the cycle involves injecting
i5 into highly compressed air i
n the working space
`
an ignition charge of
fuel oil, which is sprayed
by combustible gas under pressure. The gas
serves as the motive fuel, the oil preferably be
ing insuiiìcient in quantity to operate the en
20 gine. Regulation is h ad by varying the lift lof
the needle valve and con sequently the quantity
of gas for each injecti on.
'
' Because of the small valve lift even at full
load, mechanical means for varying the valve lift
though entirely operative, are sometimes erratic
in action particularly at light loads. In an effort
ì to improve the control characteristics recourse
Fig. 9 is a fragmentary View similar to a por
tion of Fig. 7 and showing the check valve used
in the fuel pump and omitted from the impulse
pump, the two being otherwise similar.
'
Generally stated the needle valve of the Diesel ' 5
engine is actuated by- a hydraulic plunger to
which impulses are delivered by a pump whose
delivery is Varied by an adjustable spill back.
'I'he spill back opens to connect the working space
of the pump with its -supply‘passage at a variable 10
point in each working stroke. Since the pump as
here used has no discharge valve, when the spill
back opens back flow occurs from the discharge
line, and hence from the hydraulic plunger to
the intake of the pump. To prevent heating and l5
to stabilize temperature conditions in the dis
charge line, the latter is water jacketed. Lubri
cating oil is used as the hydraulic pressure fluid.
To guard against accumulation of air in the dis
charge line, a small quantity of oil is bled each 2O
working stroke from the pump discharge to an
elevated sump from which the pump intake is fed.
Thus the oil is slowly circulated in a closed path
and progressive accumulation of air in the dis
charge line is precluded. Because of the high 25
pressures used and the high operative speed the
was had to hydraulic actuation. 'I'he hydraulic _ presence of even small amounts of air in the oil
under pressure would have a seriously disturbing
actuation and control mechanism hereinafter de
30 scribed has been found to have remarkably precise eñ'ect. Most oils carry some occluded air, but if
and uniform operating characteristics, and has any is freed in the discharge pipe it is carried 30
the commercial advantage that a standard type away by the circulatory flow, so that an objec
of Diesel fuel pump can be used (with minor tionable air volume cannot develop even by slow
accretion.
modification) as a major component.
Referring
ñrst
to
Fig.
1,
II
represents,
the
base
35 This embodiment will now be described in con
nection with the accompanying drawings, in of the engine. I2 represents one of the cylinders, 35
Fig. 1 is an end elevation of a Diesel engine em
bodying the invention.
40
Fig. 2 is a side elevati on of a portion of Fig. 1
showing the fuel oil pump and the impulse pump
for a single cylinder located side by side so as to
be actuated by cams on a single cam shaft.
Fig. 3 is a vertical axial section on an enlarged
45 scale through the cylinder
head,
the fuel injection
valve and the hydraulic means for actuating such
valve.
Fig. 4 is a. section'on the line 4_4 of Fíg.'3.
50
_
Fig. 5 is a section on the line 5_5 of Fig. 3.
Fig. 6 is a section on the line 6-6 of Fig. 3.
Fig. 7 is a vertical axial section through the
impulse pump, showing its relation to the cam
shaft.
Fig. 8 is a perspective v_iew of the pump .plunger
5 of Fig. 7, showing spill back control.
I3 is a cylinder‘head, I4 represents the exhaust
manifold and I5 the scavenging air manifold.
The invention can be applied to either single or
multiple cylinder engines of either two or four
stroke cyclefit being understood that there be. 40a separate fuel pump and impulse pump for each
cylinder, the various pumps being driven in proper
timed relation by suitably spaced cams on asingle
cam shaft. Since this involves mere- duplication
of features of the invention, it is not deemed 45
necessary to illustrate all the cylinders of a multi«
ple cylinder engine.
The lobe I6 at the left of the crank case is the
cam shaft housing and it will be observed that
the fuel pumps and impulse pumps are mounted 50
on top of this housing so as to coact with a series
of cams `on the cam shaft.
‘
'I’he device indicated at I0 is a speed governor,
here assumed to be of the well known Woodward
type. So far as is essential to the present inven- 55
2,127,165
2
To develop timed pressure impulses to actuate
tion, it suffices to point out that in response to en-V
gine speed variation the Woodward governor
causes the arm I1 to swing angularly.
Referring now to Figs. 1 and 3, there is mounted
in the center of head I3, the bonnet I8 of the fuel
Ul
injection valve. rI‘his bonnet includes a tubular
the piston 42, use is made of a pump essentially
identical with the fuel injecting pumps commonly
used in Diesel engines. It comprises a spill back
measuring pump here shown as of the type manu
factured by the United American Bosch Corpora
tion. Its construction is indicated in Figs. _k7
housing I9 which extends through the head and
seals on a shoulder 20.
and 8.
In Figure 7, 55 represents the engine cam shaft
which in a two cycle engine would be driven at 10
crank shaft speed and in a four vcycle engine
It is held down by the
flange 2| which is retained by the same studs
which hold bonnet I8 as clearly shown in Fig. 3.
Mounted within housing I9 is the tubular shell
22 externally grooved as indicated at 23 to permit
downward flow of fuel oil between shell 22 and
housing I9. A spring 24 holds the shell 22 down
4would be driven at half crank shaft speed. Shaft
55 carries a cam 56 in thrust engagement with the
roller 51 carried by the cross head 58. The spring
ward.
The needle Valve generally indicated by the
numeral 25 extends freely through shell 22 and
seats at 26 in housing |9. Below the seat 26 and
held to housing I9 by a sleeve nut clearly shown in
Fig. 3 is the nozzle-forming ñame plate 21.
20
Housing I9 has a lateral extension 28 to which the
gas and oil connections are made, the gas passage
being indicated at 29 and the oil passage at 3|)
(see Figs. 5 and 6) . Oil supplied through passage
30 iiows through grooves 23 to the space immedi
ately above seat 26. When needle valve 25 lifts,
combustible gas entering under high pressure
through passage 29 flows through shell 22 around
the stem of valve 25 and sprays the oil through
30 flame plate 21 into the ~working space of the
engine. The gas must be under a pressure higher
than the compression in the working space and
may be supplied by a compressor (not shown)
forming part of the engine (as is usual), or by
35 means independent of the engine. All that is
required is a source of gas under suñ'icient pres
sure.
The stem of .valve 25 passes through a packing
gland 3| and carries at its upper end a cross head
32 which is guided for vertical reciprocatory
motion in the housing 33.
This last is a part of
bonnet I8 and is supported thereon by the spaced
members 34. An adjustable coil compression
spring 35 urges cross head 32 downward, i. e. in a
valve closing direction.
The parts so far described do not differ mark
edly from valves heretofore used in air injection
Diesel engines.
.
A bifurcated lever 36 is pivoted at 31 on the
upstanding members 34 and carries two cylindri
cal thrust blocks 38 which underlie a hardened
steel thrust ring 39 ñxed on stem of valve 25. To
operate the lever 36, and consequently the valve
2,5, a pressure motor, whose cylinder is generally
60
59 forces the cross head downward and the key 15
and spline 6| hold it against rotation. The ele
ment 62 acts as a combined spring seat and
diverter for any oil which might leak downwardly
from the fuel pump. A drain connection (not
shown) is provided for such oil. Where the pump 20
is handling lubricating oil such diversion is not
particularly important.
The stem 63 of the cross head reacts in thrust
against the cup-shaped cross head 64 of the fuel
pump, generally indicated at 60. The stem car 25
ries an umbrella-like cap to direct oil -to diverter
62. Cross head 64 is urged downward by a spring
which is indicated at 65. The spring reacts upon
a disk 66 which embraces a head formed on the
lower end of the pump plunger 61.
The plunger 30.
61 works in a fixed bushing or sleeve 68 which has
an inlet port 69, and on the opposite side a spill
back port 10. The plunger 61 has a recess 1| pro
vided with one spiral margin 12, so formed that
rotation of the plunger on its longitudinal axis 35
will vary the time in the working stroke at which
the working space 13 above the plunger 61 is con
nected through recess 1| with- the spill back port
10. As the plunger 61 moves upward, it first dis
places oil from the working space through the pipe
connection 14 to the passage 43, heretofore de
scribed and then opens the spill back port to the
intake.
The pipe 14 is jacketed as indicated at 15, there
being inlet and‘discharge cooling water connec 45
tions, one of which appears at 16 in Fig. 3, and the
other of which appears at 11 in Fig. '1. The pur
pose of this is to establish stable temperature
conditions in the outlet, and prevent the develop
ment of heat therein. The piston displacements 50
are small, the pressures are high, and ñow
through the connecting passages is rather rapid.
While the water jacket may not be necessary in
.all cases, it is considered a desirable adjunct.
The hydraulic liquid, conveniently lubricating 55
indicated at 4|, is mounted on the cylinder head
I3. Slidable in the cylinder 4| is a free plunger
42 which is subject on its lower end to hydraulic
oil, is brought to the supply passage 69 ‘from the
elevated sump 52 by way of pipe 53 which is con
pressure communicated through the connection
43. The plunger 42 is circumferentially grooved
to minimize leakage and is in thrust engagement
the vplunger ‘61 and thus change the point in the
working stroke at which the spill back commences 60
a rotary sleeve 19 bifurcated at its lower end is
provided. The bifurcated lower end straddles the
cross plate 8| fast on theplunger stem, permitting
reciprocation of the plunger but controlling its
angular position. The sleeve 19 is angularly ad 65
justed by the toothed sector 82 which meshes with
at its upper end with a push rod 44 which engages
a roller 45 on the lever 36. A coil tension spring
46 draws the lever 36 downward.
_
Mounted near the lower end of the cylinder 4|
is a choke or bleed fitting 41 which is held in place
by the screw plug 48.
This choke fitting permits
very slow flow from the upper end of the passage
43 to'a pipe 49 which leads to the elevated sump 5|
(see Fig. 1). This sump furnishes the oil to the
70 hydraulic pressure system by way of valve 52 and
pipe 53 and serves also as a gas separation cham
ber. 'I'he elbow 54 is a drain connection for such
oil as may leak past the piston 42 and push rod 44.
It may be piped to any suitable point, such drain
75 piping not being shown in the drawings.
nected to the pump as indicated at 18. To rotate
rack teeth on a bar 83 slidably mounted in the
body of the pump.
'
Referring now to Fig. 1, the bar 83 is connected
by bell crank 84 and link 85 with the arm |1 on 70
the governor. In a multi-cylinder engine the bell
crank 84 would be part of a rock shaft extending
along the engine and connected similarly to the
adjusting rods of all the impulse units, of which
there would be one for each cylinder.
75
2,127,165;
As the governor responds to increasing speed it
moves the arm il and the rod 83 in a direction to
hasten the spill back and thus reduce the lift of
the needle valve 25. v
It is necessary to supply fuel oil through the
connection 30 to the needle valve.
To perform
. this function a second pump, substantially identi
cal with that shown in Fig. '7, is used. 'I'his pump
is indicated in Fig. 2 at 86. It may have and con
10 veniently would have an adjusting member 8l,
but this adjusting member is not operated by the
governor. On the contrary it is manually set and
then locked in position. The pump 86 delivers
fuel oil through the pipe 88 to the connection 30.
Unlike the impulse device shown in Fig. 7 the
fuel pump 86 has above the Working space' of the
pump and between it and the pipe 88, a com
bined check valve and anti-dribbling device 88
characteristic of the Bosch fuel feed pump and
for which no novelty is here claimed. The device
89 consists essentially of a check valve attached to
a small piston beneath it, the piston being pro
vided With bypass grooves. A compression spring
9i urges the valve toward its seat, preventing'back
.-flow of the oil that has been discharged on the
working stroke.
This valve
and v spring are
omitted from the impulse unit, as indicated in
Fig. ’7, because back flow is an important factor
in the use of the pump as an impulse device.
The operation of the mechanism can now be
traced. The cam which operates the fuel pump
86 is so timed that it will complete delivery of a
measured quantity of oil to the space above seat
25 of needle valve 25, shortly before the lift of
the valve commences. The cam which operates
the plunger in the impulse device 60 is properly
timed with reference to the desired time of lift of
the needle valve 25. It is given the usual slight
lead with reference to the head end dead point
of the engine piston and a slight additional lead
to compensate for a lag factor in the response of
the piston 42.
'I‘he lag is slight and has been
found to be so nearly uniform as to introduce no
material disturbing factor`
It is present, how
ever, and should be compensated for.
When the piston 6l descends it draws in oil fed
through the connection 53 and port 68. On its
ensuing upward stroke it displaces this oil through
the pipe lil, and this oil arriving through the port
¿i3 forces the piston 42 upward and lifts the needle
valve 25. 'I'his action continues until the spill
back port opens, the point of opening ybeing deter
mined by the angular position of the piston 61 as
already described. As soon as the spill back port
i opens back flow occurs from the space below the
piston 132 through the port 43 and pipe lid Aand
thence through the spill back port ‘il to the sup
` ply connection ‘I8 and pipe 53. It follows that
the prime purpose of the plunger 6l is to deliver
an impulse to the 'piston ¿i2 through oil under
pressure and then dissipate this pressure at some
chosen point in the Workingstroke of the plunger
3
ing and a smoothly graduated regulation of lift
throughout the entire load vrange of the engine.
Some idea of the precision required can be gained
from the fact that in tests with a three cylinder
17” by 25" Diesel engine, using this type of fuel
control, the valve lift never exceeded 0.044” and
the minimum of lift was of the order. of 0.008".
'I‘he improvementin regulation as compared to a
strictly mechanical control of the lift was notice
able throughout the load range and particularly
noticeable in the low load ranges in which small
lifts are encountered.
'
In certain types of air injection Diesel engines
control of the lift of the needle valve enters into
the engine regulation. In such engines the hy
draulic variable lift needle valve actuating mech
a`nism herein disclosed would be useful.
While I have shown one particular commercial
type of spill back valve, and prefer it, .other types
are known, and might be substituted without de
parture from the spirit of the invention. In cer
tain cases it may not ~be necessary to use the bleedport 4l. Its omission involves no material change
in operative principle. The Water jacket 'l5 on
the pressure pipe may also be omitted Without
change of principle. Various other changes with
in the spirit of the invention may be made by
the ' exercise of mechanical skill, and the pos
sibility of maln'ng such changes is contemplated.
What is claimed is:
30
l. The combination with an lengine of the Diesel
type having a working space; of a nozzle for in
jecting fuel into said space; a normally closed
valve controlling iiow through said nozzle; means
for supplying charges of liquid fuel to said nozzle 35
in advance of said valve; means for supplying gas
under pressure to said nozzle in advance of said
valve; a hydraulic pressure motor for opening
said valve; and means for delivering timed pres
sure impulses to said motor and comprising a re
40
ciprocating displacement plunger device driven in
timed relation by said engine and having a liquid
intake and a spill back opened to said intake at a
point in the displacement stroke of said plunger. .
2. The combination with an engine of the Diesel
type having a Working space; of :i nozzle for in
jecting fuel into said space; a normally closedvalve controlling iiow through said nozzle; means
for supplying charges of liquid fuel to said nozzle
in advance of said valve; means for supplying gas
50
under pressure to said nozzle in advance of said
valve; a hydraulic pressure motor for opening
said valve; means for delivering ‘timed pressure
impulses to said motor vand comprising a recipro
cating displacement plunger device driven in
timed relation by said engine and having a liquid 55
intake and a spill back open to said intake at a
point in the displacement stroke of said plunger;
and means for varying the point in the displace'
ment stroke at which said spill back opens.
3. The combination with an engine of the Diesel
type having a working space; of a nozzle for in
jecting fuel into said space; a normally closed
60
67, causing descent of the piston ¿l2 and the re
lated needle valve 25. The governor controls the valve controlling flow through said nozzle; means
duration of the lift impulse. The leak port ¿il ` for supplying charges of liquid fuel to said nozzle
serves each stroke to bleed from the upper end in advance of said valve; means for supplying gas 65
of the connection lll, ¿i3 ``a`\minute quantity of oil. under pressure to said nozzle in advance of said
Any air occluded in the oil would tend to accumu
valve; a hydraulic pressure motor for opening
late near the upper end of this connection, and
said
valve; means for delivering timed pressure
the function of the bleed port is to dissipate this
air as it i's freed and prevent its accumulation. impulses to said motor and comprising a recipro
eating displacement plunger device driven in
In consequence there is a minute continuous cir
culation of oil in a closed circuit but the major timed relation by said engine and having a liquid
intake and a spill back opened to said intake at
portion of the oil flow is reversed in each cycle.
The device has been found to give precise tim
a point in the displacement stroke of said plunger;
means for varying the point in the displacement 75
4
2,127,165
stroke at which said spill back opens; and a gov
ernor responsive to engine speed connected to con
trol the last named means.
4. The combination with an engine of the Diesel
type having -a working space; of a nozzle for in
jecting fuel into said space; a normally closed
valve controlling flow through said nozzle; means
for supplying charges of liquid fuel to said nozzle
in advance of said valve; means for supplying gas
under pressure to said nozzle in advance of said
valve; a hydraulic pressure motor for opening
said Valve; impulse means connected to deliver
fluid pressure impulses to said motor and com
pressure impulses to said motor and comprising
reciprocating plunger and coacting cylinder pro
vided with a liquid intake and interacting spill
back means for returning liquid to said intake,
the time of opening of said spill-back means in
each working stroke being controlled by the rela
tive angular positions of the plunger and cylinder;
means for varying such angular position; and a
governor responsive to engine speed and con
10
nected to actuate the last-named means.
6. In a Diesel `engine the combination of fuel
injecting valve; a hydraulic pressure motor for
prising reciprocating plunger and coacting cylin
der provided with a liquid intake and interacting
actuating said valve; means driven by said> engine
for developing hydraulic pressure impulses in
timed relation to the operation of the engine;
spill-backmeans for returning liquid to said in
take', the time of opening of said spill-back means
in each working stroke being controlled by the
impulses are transmitted to said motor; and
means for regulating the temperature of said
relative angular positions of the plunger and cyl
liquid.
inder; and means for varying such angular posi
tion.
5. The combination with an engine of the Diesel
type having a working space; of a nozzle for in
jecting fuel into said space; a normallyA closed
valve controlling ilow through said nozzle; means
for supplying charges of liquid fuel to said nozzle
in advance of said valve; means for supplying gas
under pressure to said nozzle in advance of said
valve; a hydraulic pressure motor for opening said
30 valve; impulse means connected to deliver fluid
means for confining a liquid through which said
20
7. In a Diesel engine the combination of fuel
injecting valve; a hydraulic pressure motor for
actuating said valve; means driven by said en
gine for developing hydraulic pressure impulses
in timed relation to the operation of the engine; 25
means for confining a liquid through which said
impulses are transmitted to said motor; and a
cooling jacket for controlling thek temperature of
said liquid.
-
‘ -JEAN J. EHRAT.
30
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