U.S. patent number 3,651,794 [Application Number 05/046,003] was granted by the patent office on 1972-03-28 for throttle for gaseous fuels.
This patent grant is currently assigned to Victor Equipment Company. Invention is credited to Lloyd A. Douglas.
United States Patent |
3,651,794 |
Douglas |
March 28, 1972 |
THROTTLE FOR GASEOUS FUELS
Abstract
An accelerator control system for an automobile employing a
gaseous fuel in an internal combustion engine, characterized by a
dome loaded pressure regulator interposed between a fuel reservoir
and an intake manifold; and a fluid sealed signal conveying unit
connected with the dome of the pressure regulator and responsive to
movement of an accelerator pedal to transmit rapidly acceleration
and deceleration signals to the pressure regulator and
correspondingly increase or decrease the intake manifold pressure.
The engine has a separate air intake manifold but its power; and,
hence, r.p.m. at a given load condition; are controlled by the
pressure regulator. Also disclosed are preferred embodiments which
employ a shut-off valve intermediate the manifold and the fuel
source, adjustable flow restrictions in conduits leading to the
individual cylinders to obtain even fuel distribution, and trim
pressure adjustment on the signal conveying unit for controlling
the idling manifold pressure. BACKGROUND OF THE INVENTION l. Field
of the Invention This invention relates to improvements in fuel
supply apparatus for internal combustion engines. More
particularly, it relates to an improved accelerator control system
for an internal combustion engine employing a gaseous fuel. 2.
Description of the Prior Art A wide variety of accelerator control
structures and systems are known in the prior art for controlling
injection of fuel; or in effecting supplemental control in a fuel
air mixture wherein fuel enrichment or derichment is effected in
response to vacuum pressure detected via an intake manifold.
Moreover, it is known to control flow of air and fuel in response
to a computer to effect an optimum fuel air ratio in an engine
being operated under fairly constant loads such as are encountered
on a pipeline. Such prior art systems have not been satisfactory in
effecting operation of an internal combustion engine on a gaseous
fuel such as natural gas in response to rapid acceleration and
deceleration changes such as effected in an ordinary driver driving
an automobile in traffic. Moreover, the prior art systems have
controlled the fuel air ratio and have not effected satisfactory
combustion without controlling the influx of the air, or other
oxygen-containing gas for supporting combustion.
Inventors: |
Douglas; Lloyd A. (Forth Worth,
TX) |
Assignee: |
Victor Equipment Company
(Denton, TX)
|
Family
ID: |
21941037 |
Appl.
No.: |
05/046,003 |
Filed: |
June 15, 1970 |
Current U.S.
Class: |
123/332; 123/529;
123/463 |
Current CPC
Class: |
F02M
21/0239 (20130101); F02M 21/0233 (20130101); Y02T
10/32 (20130101); Y02T 10/30 (20130101) |
Current International
Class: |
F02M
21/02 (20060101); F02m 021/02 () |
Field of
Search: |
;123/120,108,27GE,75B,106 ;137/505.42 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Newman; Mark M.
Assistant Examiner: Rothman; Richard
Claims
What is claimed is:
1. An accelerator control system for an automobile employing a
gaseous fuel in the cylinders of its internal combustion engine,
comprising:
a. oxygen intake means connected with said cylinders for intake of
a combustion-supporting gas; said oxygen intake means being set at
a predetermined setting independent of movement of an accelerator
pedal means in a gas flow system controlling the flow of the
gaseous fuel;
b. a source of gaseous fuel at super atmospheric pressure;
c. fuel intake manifold means comprising a fuel manifold connected
with said source of gaseous fuel, and a plurality of flow conduits;
each flow conduit being connected with said manifold and with a
respective one of said cylinders and having a check valve means
connected therewith for preventing back flow of fluid from said
cylinder to said fuel manifold;
d. a fuel cut-off valve that is operable into an open and into a
closed position for running and for stopping said engine;
e. a fuel pressure regulator that is operable to control a
downstream pressure that is substantially the same as the pressure
in said manifold from an idling pressure of a few inches of water
to a maximum running pressure of many pounds per square inch gauge
in response to a biasing element and a pressure responsive element
associated therewith; said flow pressure regulator and said fuel
cut-off valve being interposed in series connection between and
connected with said source of gaseous fuel and said fuel intake
manifold means;
f. accelerator pedal means disposed in the interior of said
automobile for imparting relatively rapid acceleration and
deceleration signals to said fuel pressure regulator; and
g. fluid sealed signal conveying means disposed intermediate said
accelerator pedal means and said fuel pressure regulator for
signalling said fuel pressure regulator to increase or decrease the
fuel manifold pressure in response respectively to the accelerate
or decelerate signal from said accelerator pedal means; said fluid
sealed signal conveying means comprising a conduit means connected
at one end with said fuel pressure regulator so as to alter the
manifold pressure as a predetermined function of the pressure in
said signal conveying means; and a pressure generating unit
sealingly connected with the other end of said conduit means and
positioned adjacent and operably responsive to said accelerator
pedal means.
2. The accelerator control system of claim l wherein said fuel
pressure regulator is a compensated, preset, dome loaded pressure
regulator, the dome of which is sealingly connected with said
conduit means of said signal conveyor means, said dome being also
sealingly connected with a diaphram serving as said pressure
responsive element of said fuel pressure regulator.
3. The accelerator control system of claim 1 wherein said flow
conduits contain respective adjustable flow restricting means for
effecting equal flow of the gaseous fuel to all cylinders.
4. The accelerator control system of claim 1 wherein said signal
conveying means contains a trim pressure adjustment means for
effecting a predetermined pressure therein for controlling the
manifold pressure and, consequently, the speed of said engine when
idling.
5. An accelerator control system for an automobile employing a
gaseous fuel in the cylinders of its internal combustion engine,
comprising:
a. oxygen intake means connected with said cylinders for intake of
a combustion-supporting gas; said oxygen intake means being set at
a predetermined setting independent of movement of an accelerator
pedal means in a gas flow system controlling the flow of the
gaseous fuel;
b. a source of gaseous fuel at super atmospheric pressure;
c. fuel intake manifold means comprising a fuel manifold connected
with said source of gaseous fuel, and a plurality of flow conduits;
each flow conduit being connected with said manifold and with a
respective one of said cylinders;
d. a fuel cut-off valve that is operable into an open and into a
closed position for running and stopping said engine;
e. a fuel pressure regulator that is operable to control a
downstream pressure that is substantially the same as the pressure
in said manifold from an idling pressure of a few inches of water
to a maximum running pressure of many pounds per square inch gauge;
said flow pressure regulator and said fuel cut-off valve being
interposed in series connection between and connected with said
source of gaseous fuel and said fuel intake manifold means;
f. accelerator pedal means disposed in the interior of said
automobile for imparting acceleration and deceleration signals to
said fuel pressure regulator; and
g. signal conveying means disposed intermediate said accelerator
pedal means and said fuel pressure regulator for signalling said
fuel pressure regulator to increase or decrease the fuel manifold
pressure in response respectively to the accelerate or decelerate
signal from said accelerator pedal means; said signal conveying
means being connected with said fuel pressure regulator so as to
alter the manifold pressure as a predetermined function of movement
of said accelerator pedal means.
6. The accelerator control system of claim 5 wherein a high
pressure regulator is emplaced intermediate said source of gaseous
fuel and said fuel pressure regulator to control the pressure
therebetween at a pressure intermediate the super atmospheric
pressure of said source of gaseous fuel and the fuel manifold
pressure; and wherein a check valve means is interposed between
each said respective cylinder and each said flow conduit in
association with a canted injection passageway which injects the
gaseous fuel into said cylinder at an angle so as to effect a
swirling motion within said cylinder and emplace the richest part
of the fuel air mixture adjacent a firing means in said cylinder.
Description
BRIEF DESCRIPTION OF THE DRAWING
The FIG. is a schematic view, partly in section, illustrating one
embodiment of this invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
It is an object of this invention to provide an accelerator control
system that is operable to control power; and, hence, revolutions
per minute (r.p.m.); by controlling only the intake manifold
pressure of a gaseous fuel in response to an accelerator pedal
means.
It is a specific object of one aspect of this invention to provide
an accelerator control system that employs a rapid conveyance, via
a pressure wave in a fluid medium, of acceleration and deceleration
signals to effect a corresponding and compensated response in the
pressure of a gaseous fuel in a fuel intake manifold, regardless of
the pressure of a fuel tank containing the gaseous fuel.
Referring to the figure, internal combustion engine 11 has a
plurality of cylinders 13 for internal combustion of a gaseous fuel
to derive power therefrom. As is conventionally employed, a piston,
connecting rod, and crank shafts are employed within the internal
combustion engine 11 to convert the chemical energy into a useable
mechanical form. A firing means; such as, a glow plug or spark plug
15; is connected via suitable conductor 17 with an electrical
distribution system for effecting timed ignition of a fuel charge
within each cylinder 13. The electrical interconnection of
conductors via an appropriate distributor and distribution system
to effect the timed ignition is well known, does not comprise a
part of this invention and need not be described herein.
Internal combustion engine 11 also has an oxygen intake means such
as air intake manifold 19. Air is drawn in through a suitable
filter 21 to remove dust and other destructive particles therefrom.
If a conventional engine having a carburetor thereon is employed,
it may be converted by simply opening the butterfly valve in the
throat of the carburetor. It is not necessary to control the flow
of air in this embodiment of this invention. The actual air intake
into the cylinder may be effected via intake valves or suitably
located ports, depending upon whether internal combustion engine 11
is a two cycle engine or a four cycle engine. The intake porting or
valving for either type of engine is well known and need not be
described herein.
Internal combustion engine 11 employs, as indicated, a gaseous
fuel. The gaseous fuel may be contained in a fuel tank 23 at super
atmospheric pressure. For example, fuel tank 23 may contain natural
gas at a pressure of up to 2,200 pounds per square inch gauge
(p.s.i.g.). Fuel tank 23 may be connected by appropriate pressure
conduit 25 with an intake manifold means at the internal combustion
engine 11. If desired, a high pressure regulator 27 may be employed
to control the pressure in pressure conduit 25 at some relatively
high pressure higher than will be desired in the fuel intake
manifold means, but lower than the pressure in the fuel tank 23;
for example, at a pressure in the range of about 50-100
p.s.i.g.
The fuel intake manifold means may comprise a fuel intake manifold
29 and a plurality of individual flow conduits 31. Each flow
conduit 31 is connected with the fuel intake manifold 29 and with a
respective one of the cylinders 13. Each flow conduit 31 has
interposed in it a check valve 33 and an adjustable flow
restricting means such as restriction valve 35. Check valve 33
prevents backflow of high pressure fluid from within cylinder 13 on
the compression stroke of the piston therewithin. Individual
restriction valves 35 are adjusted to obtain a uniform quantity of
fuel through each respective individual flow conduit 31 into each
respective cylinder 13 at a given pressure in the fuel intake
manifold 29. Thus, uniform power is developed in each respective
cylinder regardless of the pressure on fuel intake manifold 29.
Preferably, the actual injection passageway 37 and check valve 33
are closely adjacent the internal chamber of cylinder 13 with
injection passageway 37 canted so as to deliver a charge of gaseous
fuel that, in combination with the entering air, effects a swirling
movement so that the fuel is directed toward the center of the
cylinder 13. In this way, the richest portion of the fuel air
mixture will occur adjacent spark plug 15 so as to always effect
ignition of the fuel regardless of how lean the fuel air mixture
becomes adjacent the peripheral wall of the cylinder 13.
A fuel cut-off valve that is operable into an open and into a
closed position for running and stopping the internal combustion
engine 11 is interposed between and in series connection with fuel
intake manifold 29 and fuel tank 23. Specifically, solenoid
actuated valve 39 is interposed in conduit 41 so as to be
electrically operable into an open position for starting the engine
and into a closed position for stopping the engine. Its associated
solenoid 43 may be a self-latching relay such that when pulsed, as
by turning an ignition key on or off, it is energized electrically
or mechanically into and remains in a corresponding position until
oppositely pulsed; or, it may be maintained energized all the time
the ignition key is on to maintain the valve 39 open. While cut-off
valve 39 may be interposed at any location intermediate fuel tank
23 and fuel intake manifold 29, it is preferably located downstream
of fuel pressure regulator 45 so that a low pressure valve may be
employed.
The fuel pressure regulator 45 is interposed in series connection
with cut-off valve 39 between fuel intake manifold 29 and fuel tank
23. The fuel pressure regulator 45 is operable to control a
downstream pressure that is substantially the same as the pressure
in the fuel intake manifold. Normally, the pressure in the fuel
intake manifold runs from an idling pressure of only a few inches
of water to a maximum running pressure of several or even many
p.s.i.g. Preferably, the pressure regulator 45 has a biasing
element such as spring 47 and a pressure responsive element such as
diaphram 49. Spring 47 is pre-set to effect a predetermined
downstream pressure at atmospheric pressure on diaphram 49. The
compressive force on spring 47 may be effected by a suitable screw
passed through a threaded aperture. The screw is thus pre-set at
the factory, although it may be altered by removing a portion of
the dome and; for example, screwing inwardly to increase the
pressure. As illustrated, however, dome 51 is dome loaded. That is,
it is sealingly connected with diaphram 49 and not vented to the
atmosphere. Thus, the dome pressure acting on diaphram 49 may be
altered to increase or decrease the downstream pressure. Fuel
pressure regulator 45 may be of the single stage compensated type
such as described in copending application Ser. No. 827,711, by Ray
R. Zimmer entitled "Single Stage, Compensated Pressure Regulator,"
and assigned to the assignee of the present invention, or it may be
a two stage compensated regulator. The compensation is preferably
employed to obtain accurate and predictable response in effecting a
desired manifold pressure regardless of the pressure in fuel tank
23. Such compensation becomes less critical if a high pressure
regulator 27 is employed although it is still desirable if the fuel
pressure in fuel tank 23 becomes less than the pressure for which
the high pressure regulator 27 is set.
An accelerator pedal means is disposed in the interior of the
automobile for imparting relatively rapid acceleration and
deceleration signals to the internal combustion engine 11.
Specifically, a foot accelerator pedal 53 is pivotally mounted on
mounting 55. Foot accelerator pedal 53 is depressed to signal an
acceleration signal and is allowed to spring upwardly to signal a
deceleration signal to the fuel pressure regulator 45. Fuel
pressure regulator 45, in turn, controls the pressure in the fuel
intake manifold 29 and, consequently, the power output from the
internal combustion engine 11.
A fluid sealed signal conveying means is disposed intermediate the
accelerator pedal means and the fuel pressure regulator for
signaling the fuel pressure regulator to increase or decrease the
fuel intake manifold pressure in response to the respective
acceleration or deceleration signal from the accelerator pedal
means. The fluid sealed signal conveying means 57 comprises a
conduit means 59 and a pressure generating unit 61. The conduit
means 59 is connected with dome 51 of the fuel pressure regulator
45 so as to alter the manifold pressure as a predetermined function
of the pressure in the signal conveying means 57. The pressure
generating unit 61 is connected with the other end of the conduit
means and positioned adjacent and operably responsive to the
accelerator pedal means illustrated as foot accelerator pedal 53.
As illustrated, dome 51 is sealingly connected with the conduit
means 59 such that any pressure generated by pressure generating
unit 61 is transmitted directly to diaphram 49 and a predetermined
and corresponding change in downstream pressure thereby effected.
Thus, an acceleration signal, denoted by depression of foot
accelerator pedal 53, is conducted with the speed of the pressure
wave via conduit means 59 to diaphram 47 to signal the fuel
pressure regulator 45 to increase the downstream pressure, or fuel
intake manifold pressure. Conversely, releasing foot accelerator
pedal 53 signals a decrease in fuel intake manifold pressure via
the same route.
The pressure generating unit 61 has a centrally disposed diaphram
member 63 that is disposed adjacent and responsive to shaft 65,
which is, in turn, responsive to movement of foot accelerator pedal
53. Shaft 65 may be connected with diaphram member 63 as by a nut;
and with foot accelerator pedal 53 as by a pivot pin; or otherwise
held as by being compressively disposed therebetween. Spring 67
beneath diaphram member 63 biases diaphram member in the opposite
direction to decrease the pressure in the pressure generating unit
61 when the foot accelerator pedal 53 is released. Expressed
otherwise, diaphram member 63 is depressed to increase the pressure
by downward movement of accelerator pedal 53 and is moved in the
opposite direction of decrease the pressure in the dome 51 by the
spring 67.
The signal conveying unit may be filled with either a gas or a
liquid. A gas such as air affords a convenience in loading and is
economical. On the other hand, a liquid has less compressibility
and effects a more rapid response to the acceleration or
deceleration signals.
A trim pressure adjustment means is provided for effecting a
predetermined pressure in the dome 51 at a given setting of the
accelerator pedal for controlling the manifold pressure at the
idling speed of the engine. Specifically, a screw 69 is sealingly
inserted in a threaded aperture 71 in pressure generating unit 61
such that the diaphram member 63 may be positioned at any point to
effect a given quantity of the fluid in the signal conveying means
57. Screw 69 is thereafter inserted to trap the fluid therein and
effect the predetermined pressure. In addition, the pressure may be
adjusted precisely by increasing or decreasing the volume minutely,
as by screwing screw 69, respectively, outwardly or inwardly.
In operation, a given quantity of fluid is entrapped in signal
conveying means 57 and the foot accelerator pedal 53 allowed to
rest at a desired position. Once set, little further adjustment
need be made. The ignition key may be turned on to open solenoid
valve 39 and connect the fuel intake manifold 29 with the fuel
pressure regulator 45 for starting the engine. The engine is
started in the conventional manner. Upon a signal to accelerate,
fuel pressure regulator 45 increases the pressure in the fuel
intake manifold 29 from a few inches of water to several p.s.i.g.,
depending upon the degree of acceleration signalled by the
driver.
Within the individual cylinders, air is taken in at a relatively
constant rate if there is no adjustable butterfly or obstruction.
On the intake, when the pressure in the cylinder gets below the
pressure in the fuel intake manifold, the gaseous fuel flows
through check valve 33 and through canted passageway 37 into the
interior of cylinder 13. If internal combustion engine 11 is a two
cycle engine this fuel flow occurs on every stroke. Alternatively,
if it is a four cycle engine the fuel flow may occur on every
stroke if desired to sweep out the exhaust gases; or it may be
valved such that the fuel gas is taken into the cylinder only on
the compression stroke. In any event, the gaseous fuel is admixed
with the air; although not necessarily uniformly, since it is
preferably richer in the central portion adjacent the spark plug,
or the glow plug. At the proper time, as determined by a
distributor, the fuel is ignited and burned in cylinder 13 for
delivering power during the expansion stroke. If it is desired to
decelerate, the foot is removed from the foot accelerator pedal and
the diaphram member 63 moves backwardly, or upwardly, decreasing
the pressure in dome 51 and on diaphram 49. This effects a
decreased downstream pressure and a decreased pressure in the fuel
intake manifold 29. Consequently, less fuel is delivered to the
cylinder 13 and lower power is realized from the engine. There is a
concomitant slowing of the automobile. If acceleration is again
signalled by depression of the foot accelerator pedal, diaphram 49
senses the increased pressure and increases the fuel pressure in
the fuel intake manifold 29. Consequently, a greater amount of fuel
enters the cylinder 13 to deliver a greater amount of power.
When it is desired to kill the engine, cut-off valve 39 is closed
to cut off the flow of fuel thereto.
A preferred embodiment has been described hereinbefore in which a
fluid filled signal conveying means is employed intermediate a foot
accelerator pedal and a fuel pressure regulator for controlling the
pressure of the fuel in a fuel intake manifold. If desired, other
embodiments, such as, a mechanical connection between the foot
accelerator pedal and a spring balanced diaphram in the fuel
pressure regulator; could be employed to control the fuel pressure
in the fuel intake manifold. Such embodiments may have, however,
aspects that are not as advantageous as the preferred embodiment
described hereinbefore.
One of the advantages of this invention is that no exotic new
materials are required but those materials ordinarily employed in
manufacturing pressure regulating elements, valves and engine
parts, may be employed herein. One advantage that has been found
with this operation, in which the richest fuel air mixture is
adjacent the glow plug 15, is that, if desired, the electrical
charge to the glow plug 15 can be reduced after the engine has been
warmed up and still effect satisfactory combustion.
It can be seen from the foregoing descriptive matter that this
invention provides an accelerator control system that obviates the
disadvantages of the prior art devices and controls the power; and,
hence, rpm at a given load; by controlling only the intake manifold
pressure for a gaseous fuel in response to an accelerator pedal
operation. It also can be seen that this invention provides an
accelerator control system that employs a fast response in one
aspect, via a pressure wave in a confined fluid medium, to convey
the acceleration and deceleration signals to a pressure regulator
that correspondingly and responsively controls pressure of a fuel
intake manifold to regulate the power provided by an internal
combustion engine.
Although the invention has been described with a certain degree of
particularity, it is understood that the present disclosure is made
only by way of example and that numerous changes in the details of
construction and the combination and arrangement of parts may be
resorted to without departing from the spirit and the scope of the
invention.
* * * * *