Variable displacement fuel pump for internal combustion engine

Danskin, J. H.

English

NASA Technical Reports Server

Feb. 3, 1970 T. O. PAJNE 3,492,947 
ACTING ADMINISTRATOR O F  T H E  NATIONAL 
AERONAUTICS A N D  SPACE ADMINISTRATION 
FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES 
Filed Feb. 10, 1969 3 Sheets-Sheet 1 
https://ntrs.nasa.gov/search.jsp?R=19710004583 2020-03-17T02:33:18+00:00Z
Feb. 3, 1970 T. O. PAINE 3,492,947 
ACTING ADMINISTRATOR OF T H E  NATlONAL 
AERONAUTlCS A N D  SPACE ADMlNlSTRATlQN 
FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES 
F i l e d  Feb. 10, 1969 3 Sheets-Sheet 2 
John M D@nskin 
/NVEN TOR 
Feb. 3, 1970 T. O. PAINE 3,492,947 
ACTING ADMINISTRATOR O F  THE NATIONAL 
AERONAUTICS A N D  SPACE ADMlNlSTRATlON 
FUEL INJECTION PUMP FOR IKTERNAL COMBUSTION ENGINES 
Filed Feb. 10, 1969 3 Sheets-Sheet 3 
John H D o I Y s ~ . ~ ~  
;United St,ates Patent Ofice 3,492,947 Patented Feb. 3, 1970 
quantity of fuel to each respective engine cylinder under 3,492,947 
FUEL INSECmON PUMP FOR INTERNAL all load conditions becomes quite complex for this pur- 
CO1&rPIUSTION ENGINES pose. 
T. 0. Paine, Acting Administrator of the National Aero- Accordingly, direct injected fuel delivery systems for 
wautics and Space Administration, with respect to an 5 1.C. engines have not been widely accepted by the in- 
invention of John H. Danskin, Northridge, Calif. dustry due to the manufacturing and maintenance econom- 
Filed Feb. 10, 1969, Sea. No. 797,796 ics associated with fuel injection pumps of the prior art. 
Int. Cl. FO4b 49/00, 19/02 In lieu thereof, aspirated fuel systems have been adopted 
U.S. @I. 103-37 4 Claims by a majority of the I.C. power industry notwithstanding 
10 the compromise of operational efficiency incident thereto. 
ABSTRACT OF THE DISCLOSURE It is, therefore, an object of this invention to teach the construction of a fuel injection pump that is adapted 
A variable displacement volume fuel injection pump to inexpensive manufacturing an2 maintenance iech- 
for internal combustion engines comprises an axially re- niques. 
ciprocating tubular displacement plunger (d.p.) having 15 A further object of this invention is to provide a reci- 
an axial through-bore. The pump cylinder head end of the procating element pump in which the fluid discharge 
d.p. is resiliently biased to a constant first position remote quantity may be rapidly and continuously adjusted. 
from the pump cylinder head and is driven against the Another object of this invention is to provide a vari- 
force of said resilient bias by an engine cam driven rocker able discharge volume system for a multielement recipro- 
arm to a constant second position more proximate of 20 cating pump that is simple to calibrate and operate. 
said cylinder head. Reciprocally disposed within said d.p. 
through-bore is a cylindrical volume control plunger SUMMARY 
(v.c.p.) that is resiliently biased to a constant first posi- To accomplish the foregoing objects, a fuel injection 
tion proximate of said cylinder head and is extruded cylinder according to the present invention is 
against the bias thereof through said through-bore to a 25 provided with a tubular displacement plunger (d.p.) hav- 
variable second position, determined by the position of ing an axial through-bore. The d.p. extends beyond the 
a s~lectively variable abutment surface, by the pressure axial end of the pump cylinder and has a disposed 
force of a charge of fuel in said cylinder displaced by about the periphery thereof. A coil spring seated between 
said d . ~ .  upon moving from said first to said second a portion of the pump housing structure and the proximate 
respective positions. The volume of fuel displaced by 30 side of the d.p, collar urges the d.p. away from the head 
said d.p. in moving from said first to said second respec- end of the pump cylinder. On the side of the d.p. collar 
tive positions equals or exceeds the volume evacuated by opposite from the spring seat, an engine cam driven rocker 
said V.C.P. upon extrusion from the first to the second arm forces the reciprocation of the d.p. toward the cyl- 
positions respective thereto. The excess fluid volume dis- inder head end against the bias of the spring. 
placed by said d.p. is discharged from the Pump cylinder 35 Within the d.p. through-bore, a solid cylindrical volume 
Part a resiliently biased check valve into a Pump dis- control plunger (v.c.p.) is slidably disposed to axially 
charge conduit. reciprocate therein. A portion of the v.c.p. projecting 
beyond the d.p. collar end is provided with an abutment 
40 surface which engages a co-operative, selectively position- 
ORIGIN OF THE INVENTION able, abutment surface to limit the extrusion of the v.c.p. 
The invention described herein was made in the per- when the Pump cylinder Pressure becomes sufficiently 
formance of work under a NASA contract and is subject great as to force the V.C.P. out through the d.p. through- 
to the provisions of section 305 of the National Aeronau- bore against the bias of another spring urging the v.c.p. 
tics and Space Act of 1958, Public Law 85-568 (72 Stat. 45 toward the cylinder head end. 
435, 42 U.S.C. 2457). In operation, the fluid admitted to the cylinder pres- 
BACKGROUND OF THE INVENTION 
The efficient operation of internal combustion engines 
designed to exploit thermodynamic principles embodied in 
Otto and Diesel cycles, for example, relies upon the ability 
of the machine to provide the correct ratio of fuel and 
oxidant to the combustion chamber thereof in quantities 
proportional to the power demanded from the engine. 
Furthermore, the resvective auantities of fuel and oxidant 
must be correctly a i d  homogeneously combined within 
the engine combustion chamber to constitute a combustible 
charge. 
Theoretically, the above objectives are best accom- 
plished in an air breathing engine, naturally inducted or 
supercharged, by injecting the fuel directly into the com- 
bustion chamber under sufficiently high pressure as to  
cause complete vaporization and mixing. 
sure chamber from intake conduits is trapped between 
the fluid end of the d.p. and the cylinder head with the 
annulus that is formed by the cylinder wall and the outer 
peripheral wall of the v.c.p. As the d.p. continues its in- 
50 ward stroke, the pressure on the trapped fluid forces 
the v.c.p. out through the d.p. through-bore with the vol- 
ume evacuated by the v.c.p. equaling that displaced by 
the d.p. The extrusion of the v.c.p. continues until the 
co-operative abutment surfaces engage to halt the extru- 
55 sion. Depending on the position of the adjustable abut- 
ment surface. the d.p. may have a portion of stroking 
distance remaining whereupon the fluid pressure is further 
increased to overcome the sealing pressure of a check 
valve disposed in the fluid discharge conduit for high 
pressure fluid delivery. 
BRIEF DESCRIPTION OF THE IDRAWNGS 
In the& functions are performed by fuel injec- These and other objects of the present invention may 
tion pumps usually having a pumping piston and cylinder be more readily seen and understood by reference to the 
element respective to each power cylinder in the engine. following detailed description of the drawing wherein: 
As an additional complicating factor, each of these pump FIGURE 1 is a cross-sectional elevation of a typical 
elements must include some mechanism for regulating the pumping unit constructed according to the invention. 
quantity of fuel delivered on each pulse responsive to the FIGURE 2 is a partial view of the pump illustrated in 
instantaneous power demand from the engine. In the FZG. 1 showing the relative positions of key pump and 
case of a multicylinder engine, the calibration of prior volumetric control elements at the fluid intake portion 
art mzchanisms so that each element delivers a uniform of the pumping cycle. 
3,492,947 
3 4 
FIGURE 3 is a partial view of the pump illustrated determined pressure. The preset tension in spring 37 
in FIG. 1 showing the relative positions of key pump determines the cracking pressure at which obturating ele- 
and volumetric control elements at the fluid discharge ment 36 will move away from its associate seat to allow 
portion of the pumping cycle. fluid to flow from cylinder 17 into discharge conduit 3. 
DESCRIPnON OF THE PREFERRED 5 OPERATION 
EMBODIMENT It will be readily seen from a cursory purview of FIG. 
With reference to FIG. 1, there is shown the cross- 1 that the linear displacement of bell crank 7 hammer 
section of what may be a single pumping unit of a multi- end 12 is determined by the product of the radial dif- 
pie unit pump. When used as a reciprocating internal 10 ferential between the cylindrical surface of cam 5 and 
combustion (i.c.) engine fuel injection pump, there will lobe 6 multiplied by the length ratio of bell crank fol- 
usually be a number of pumping units equal to the num- lower arm 8 length to the hammer arm length. This linear 
ber of power cylinders in the associate engine. displacement will dictate the reciprocating stroke of dis- 
The body 1 of the pump is provided, for each pumping placement plunger 13 and hence, the volume of cylinder 
unit, a fuel inlet conduit 2 which may communicate with 15 17 displaced thereby. 
a pressurized distribution manifold not shown. Also pro- A typical pumping cycle is initiated by cam follower 
vided for each pumping unit is a discharge conduit 3 8 contacting the cylindrical portion of cam shaft 4 as 
which may communicate at the terminal end thereof with illustrated in FIG. 1. Accordingly, hammer surface 12 
injector nozzles for discharging a precisely metered of bell crank 7 is rotated to the maximum clockwise di- 
quantity of fuel directly into the engine combustion 20 rection thereby allowing the bias of spring 14 to push 
chamber in a fine mist conducive of rapid mixing and displacement plunger 13 to the maximum withdrawn 
vaporization with an air charge. Bearing journals 4 are position relative to cylinder head 38. See FIG. 2.  In this 
provided to rotatively support an engine driven cam shaft position, the intake conduit 18 penetration points of 
S having lobes 6. Cam shaft lobes 6 cause the oscilla- cylinder 17 are open to allow fluid to flow into and fill 
tion of bell crank 7 by turning against the cam follower 25 the cylinder void. 
8 rotatively supported at one bell crank end. Simultaneously, the biasing force of metering plunger 
The other end of the bell crank 7 is provided with an spring 25 prevails over the cylinder 17 pressure force 
aperture 9 for reasons to  become obvious subsequently. acting on the cross-sectional area of volume control 
The internal bore of aperture 9 should be crowned to plunger 20 thereby pushing the fluid end face of volume 
avoid structural interference between the aperture walls control plunger 20 to the maximum inward position 
and the driving end 11 of the displacement plunger 13 relative to cylinder head 38. 
as the bell crank oscillates about the axis of rocker shaft Because of the presence of volume control plunger 20 
10. Hammer surface 12 is also crowned and hardened in cylinder 17, the maximum cylinder void to be filled by 
for striking displacement plunger collar 14. incoming fluid is essentially limited to the annular space 
A spring seating collar 15 is provided to abut the 35 between the fluid end face of displacement plunger 13 
under surface of collar 14 and act as a seat and reac- and the cylinder head 38. 
tion surface for displacement plunger biasing spring 16. As the cam 5 rotates such that the follower 8 is con- 
The pump cylinder 17 is provided with a plurality of tacted by lobe 6, hammer surface 12 acts against dis- 
intake conduits 18 emanating radially inward from a placement plunger collar 14 to force the displacement 
manifold ring 119 which is in fluid communication with '(' plunger inwardly toward cylinder head 38 against the 
f ~ ~ e l  inlet conduit 2. The penetration point by intake con- bias of spring 16. The consequence of this displacement 
duits 18 of cylinder wall 17 is determined by the cylinder of plunger 13 is to seal the intake conduits 18 as the 
fill rate at maximum pump operational speed. Co-opera- plunger moves inwardly (FIG. 3 )  and displace the Auid 
tively, said penetration point determines the maximum ex- trapped in the annulus between displacement plunger fluid 
tracted position of the fluid end-face of displacement 45 end face and cylinder head 38. To accommodate the fluid 
plunger 13. displaced by this action, the bias force of metering plunger 
Slidably disposed within the hollow interior of displace- spring 25 is exceeded and volume control plunger 20 is 
ment plunger 13 is a solid cylindrical rod-like volume extruded from the cylinder 17. Such extrusion continues 
control plunger 20. The volume control plunger projects until the inclined abutment surface 24 of metering plunger 
axially beyond the driving end 11 of displacement plunger 50 22 contacts the inclined abutment surface 32 of metering 
13 and is provided with an end collar 21. The upper face wedge 28. M e n  this occurs, the continued inward advance 
annulus of end collar 21 is engaged by the co-operative of displacement plunger 13 raises the pressure of the fluid 
end of metering plunger 22. trapped in cylinder 17 sufficiently to overcome the sealing 
Metering plunger 22 is constructed 'with a stirrup open- force exerted by spring 37 on the obturating element 36 
ing 23 having an inclined abutment surface 24. Spring 55 in the discharge orifice 35. Accordingly, a quantity of fluid 
25 serves to bias metering plunger 22 into firm engage- equal to the volumetric displacement of displacement 
ment with the upper face annulus of end collar 21. Set plunger 13 after the abutment of metering plunger 22 
screw 26 provides an adjustable seating surface for spring with wedge 28 is discharged into conduit 3 under high 
25 to regulate the biasing force thereof. pressure. 
To limit and control the reciprocatory displacement of 60 As will be observed from FIG. 1 the extent to which 
metering plunger 22 between abutment surfaces 24 and volume control plunger 20 is extruded from cylinder 17, 
27, a metering wedge 28 is provided to project through thereby determining the quantity of fluid discharged into 
stirrup opening 23. Movement of the metering wedge 28 conduit 3, is a function of where, along the length of in- 
is restricted by parallel surfaces 30 and 31 of the pump clined surface 32, metering plunger 22 strikes the wedge 
body 1 to reciprocatory motion in the direction indicated 65 218. This relation is regulated by the selective positioning 
by arrow 29. Inclined abutment surface 32 of metering of wedge 28 along the line indicated by arrow 29. Such 
wedge 28 is constructed with approximately the same regulation of the wedge 28 position is executed by the. 
slope as that of metering plunger inclined abutment sur- engine throttle mechanism. 
face 24. Obviously, many modifications and variations of the 
In order to limit the reciprocatory motion of meter- 70 present invention are possible in the light of the above 
ing wedge 28, a limiting slot 33 may be provided in wedge teachings. For example, the throttling mechanism including 
28 to co-operate with limiting pin 34. the metering wedge 28 and plunger 22 may be supplanted 
Referring finally t o  the discharge orifice 35 from cyl- by other mechanisms which will provide a selectively po- 
inder 17, a resiliently biased check valve obturating ele- sitionable abutment surface for limiting the extruded dis- 
ment 36 is providgd to seal the cylinder against a pre- 75 placement of volume control plunger 20. The term re- 
3,492,947 
5 6 
ciprocation, as used in the following claims, is intended second plunger means strikes sald seletclvely posi- 
to also encompass the technical definition of oscillation. tionable abutment means wheieupon substantially 
Furthermore, such geometrically descriptive terms as all Buid displaced by said first plunger means after 
cylindrical are intended to encompass other shapes such said abutment means striking is discharged into said 
as elliptical and toroidal that are compatible with the discharge conduit means. 
spirit of the invention. 2. Apparatus as described by claim 1 wherein said 
What is claimed is: first tubular plunger means is provided with radnally pro- 
1. A fuel injection pump for internal combustion en- jecting abutment surface means having annular face 
gincs comprising: means, the approximate plane of said annular face means 
pump body means; disposed substantially perpendicular to said first plunger 
cylindcr means in said body having an open bore end axis, said annular face means being positioned between 
and head end; said cylinder bore end of said first plunger means and 
inlet fluid conduit means communicating with said said cylinder bore end of said cylinder. 
cylinder intermediate of said ends; 3. Apparatus as described by claim 2 wbcrein said 
discharge fluid conduit means communicating with said 15 powered stroking means comprises cam means, said cam 
cylisder proximate of said head end; means acting upon said annular face means to force said 
fiist tubular plunger means having an axial through- first plunger means to said second position; 
bore disposed for axial reciprocation within said said first resilient bias means acting upon said annular 
cylinder means and extending beyond said bore end; face means to urge said first plunger to said finst 
second cylindrical plunger means disposed for axial 20 position. 
reciprocation within the through-bore of said tubular 4. Apparatus as described by claim 3 wherein said cam 
plunger means, said second plunger means extend- means comprises substantially cylindrical aperture means 
ing beyond the bore end of said first plunger means; and annular striking face means, the approximate plane 
first resilient biasing means urging the head end of said of said striking face means disposed substantially per- 
rilst plunger means to a first position most remote 25 pendicular to the axis of said cylindrical apertune means; 
from said cylinder head end; a portion of said first plunger means between the cylin- 
second resilient biasing means urging the head end of der bore end thereof and said first plunger annular 
said second plunger means to a first position most face means being slidably disposed within said 
proximate of said cylinder head end; cylindrical aperture means. 
powered stroking means forcing said first plunger 30 
means to a second position most proximate of said References Cited 
cylinder head end; 
selectively positionable abutment means limiting the UNITED STATES PATENTS 
withdrawal of said second plunger means to a vari- 2,301,435 11/1942 Mercier ------------- 103-37 
able second position remote from said cylinder head 35 2,470,380. 511949 Turnwald -------- 103-37 XR 
end; and 2,821,926 2/1958 Miller -------------- 103-37 
resiliently biased unidirectional flow control means dis- 2,839,002 6/1958 Williams -------- 103-158 
posedin said dicharge fluid conduit means whereby 
the fluid pressure force imposed on a fluid fuel charge FOREIGN PATENTS 
in said cylinder by said first plunger means in mov- 40 632,730 12/1961 Canada. 
ing from first to second respective positions exceeds 370,534 4/1932 Great Britain. 
the fluid pressure force required to  move said second 
plunger from first to second respective positions L. FREENI, Primary Examine* 
against the force of said second biasing means but 
is less than the fluid pressure force required to open 45 U.S. C1. X.R. 
said unidirectional flow control means until said 103-158 


Fuel injection pump for internal combustion engines Patent

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