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United States Patent 5,315,977
Fosseen May 31, 1994
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Fuel limiting method and apparatus for an internal combustion vehicle
Abstract
A method and apparatus for limiting the fuel to an internal combustion engine to
reduce emissions of the engine. Means responsive to one or more operating
conditions of the engine are provided for adjustably setting the maximum open
position of a throttle of the engine so as to reduce and limit the maximum fuel
volume flow rate to the engine. The operating conditions include the fuel flow
rate called for by an accelerator, the condition of the transmission of a
vehicle in which the engine is installed, the slope or incline on which the
vehicle is located, the vehicle speed, and the speed and direction of any wind.
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Inventors: Fosseen; Dwayne (206 May St., P.O. Box 10, Radcliffe, IA 50230)
Appl. No.: 688306
Filed: April 22, 1991
U.S. Class: 123/357; 123/370
Intern'l Class: F02M 037/04
Field of Search: 123/320,373,367,462,357,358,359
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References Cited [Referenced By]
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U.S. Patent Documents
<TABLE>
<S> <C> <C> <C> <C>
4090785 Feb., 1980 Montgomery 123/359.
4223654 Sep., 1980 Wessell 123/358.
4243004 Jan., 1981 Ritter 123/358.
4453516 Jun., 1984 Filsinger 123/357.
4502437 Mar., 1985 Voss 123/357.
4502438 Mar., 1985 Yasohara 123/357.
4502440 Mar., 1985 Fronk 123/358.
4566068 Jan., 1986 Iwasaki 123/357.
4566414 Jan., 1986 Sieber 123/357.
4850320 Jul., 1989 Wokan 123/359.
4917063 Apr., 1990 Hiraki 123/357.
4917065 Apr., 1990 Law 123/370.
4972819 Nov., 1990 Engfer 123/370.
</TABLE>
Primary Examiner: Miller; Carl S.
Attorney, Agent or Firm: Herink; Kent A., Laurenzo; Brian J., Trout; Brett J.
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Claims
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1. Fuel limiting apparatus for an internal combustion engine operably connected
to a transmission capable of being operated in a first gear and a second gear,
the apparatus including throttle means through which fuel is supplied to the
engine controlled by an accelerator, comprising:
a. means for limiting to a first value the maximum fuel flow rate through the
throttle means called for by the accelerator to thereby reduce maximum power
output of the engine to a first power output, wherein said first power output is
less than an unrestricted power output of the engine resulting from an
unrestricted fuel flow through the throttle;
b. means for increasing to a second value the maximum fuel flow rate through the
throttle means called for by the accelerator to thereby increase said maximum
power output of the engine to a second power output, said second power output
being greater than said first power output;
c. wherein said first value limiting means reduces said maximum power output of
the engine to said first power output when the transmission is being operated in
the first gear; and
d. wherein said second value increasing means increases the maximum power output
of the engine to said second power output when the transmission is being
operated in the second gear.
2. Fuel limiting apparatus for an internal combustion engine installed in a
vehicle, the engine including throttle means through which fuel is supplied to
the engine controlled by an accelerator, comprising:
a. means for limiting to a selected one of a plurality of fixed values the
maximum fuel flow rate through the throttle means called for by the accelerator
to thereby reduce the maximum power output of the engine;
b. means for sensing the incline of the vehicle; and
c. wherein said maximum fuel flow rate is adjusted in response to vehicle
acceleration according to a preselected schedule.
<PAGE>
3. Fuel limiting apparatus as defined in claim 1 wherein the engine is installed
in a vehicle and further comprising means for sensing the acceleration of the
vehicle and wherein said selected fixed value of said maximum fuel flow rate is
adjusted in response to vehicle acceleration according to a preselected
schedule.
4. Fuel limiting apparatus as defined in claim 1 wherein said selected fixed
value of said maximum fuel flow rate results in a decrease in emissions from
said engine.
5. Fuel limiting apparatus as defined in claim 1 wherein said second power
output is equal to said unrestricted power output of the engine resulting from
said unrestricted fuel flow through the throttle.
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Description
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BACKGROUND OF THE INVENTION
The invention relates to a fuel limiting apparatus for an internal combustion
vehicle and, more specifically, to an apparatus used to modify an internal
combustion vehicle so that the maximum rate of fuel supplied to the engine is
restricted according to a preselected schedule dependent upon the speed of the
vehicle, the gear state of the transmission, or other operating conditions.
In the manufacture of internal combustion vehicles, the engines are typically
sized to provide power to meet the maximum requirements of the particular
application and design constraints of the vehicle. Operating conditions of the
vehicle, however, vary over a wide range of power demands, particularly when
considerations are made for fuel economy and reduction of polluting emissions
from the vehicle. For example, as is well known, substantial amounts of fuel are
wasted by full acceleration starts wherein the engine is over-fueled under the
transient conditions. It is just being understood and appreciated that such full
acceleration starts also result in substantial increases of emissions from the
engine, particularly in the form of hydrocarbons and particulates. In an
over-fuel condition, the engine is unable to burn fully all of the fuel with the
result that uncombusted hydrocarbons are emitted. Such conditions also reduce
the temperature of the combustion chamber which leads to an increase in the
formation of particulate emissions.
The use of the full capacity of the engine power, particularly for high
acceleration at low speeds, produces excessive stresses on the engine, the drive
train of the vehicle, the suspension, and other components. While these effects
have been long recognized and discouraged both by public agencies as well as
private fleet owners, there has been heretofore no suitable way of forcing
compliance with the recommended guidelines.
<PAGE>
SUMMARY OF THE INVENTION
The invention consists of an apparatus for modifying an internal combustion
vehicle so that the maximum rate of fuel supplied to the engine is limited to a
preselected schedule that is determined according to the speed, condition of the
vehicle transmission and/or acceleration conditions of the vehicle. The
invention can take a number of specific forms corresponding to the particular
internal combustion engine and vehicle on which it will be practiced. For
example, with engines having sophisticated electronic control apparatus, the
present invention would consist of a plurality of sensors attached to a central
processing unit which is interconnected with and controls the electronic control
apparatus of the internal combustion engine. Such sensors would detect and
provide information to the central processing unit regarding the speed of the
vehicle, the condition of the transmission of the vehicle, the attitude of the
vehicle (whether it is on an up hill or down hill incline), any headwind
conditions, and the position of the accelerator pedal that is ordinarily used to
determine the demand for fuel to be supplied to the engine. The central
processing unit would compare the conditions detected by the sensor with the
preselected schedule of fuel rate that had previously been stored in a memory
device. If the rate of fuel supply being demanded by the accelerator exceeded
that of the schedule, the central processing unit would send a signal to the
electronic control apparatus of the engine to restrict the rate of fuel being
supplied to the engine to the preselected schedule amount.
In an alternative embodiment applicable to internal combustions which have
mechanical means for controlling the rate of fuel supplied to the engine, the
central processing unit controls a stepper motor which moves an adjustable stop
for the fuel rate supply apparatus of the engine again to restrict the maximum
rate of fuel to that of the preselected schedule.
In a third, less sophisticated embodiment, a plurality of linear actuators are
used to adjust a stop for the fuel rate control apparatus of the engine. The
actuators are adjusted to move the stop to a preselected position for each of
the gears of the transmission of the vehicle. Accordingly, the maximum rate of
flow of fuel that will be supplied to the engine when the vehicle is in the
first or lowest gear of the transmission is set by the first linear actuator. A
second, somewhat higher maximum amount of fuel rate is set to a preselected
amount by movement of the stop by the second linear actuator, and so on for each
of the higher gears.
With respect to each of the embodiments, the power lost due to limiting of the
primary fuel of the engine can be partially compensated by the addition of a
hydrous alcohol fuel into the intake manifold of the engine.
Accordingly, it is an object of the present invention to provide an apparatus
for modifying an internal combustion vehicle to restrict the maximum flow rate
of fuel to the engine according to a preselected schedule that is dependent on
the speed of the vehicle.
<PAGE>
Another object of the invention is to provide such an apparatus wherein the
schedule is substantially continuous with changes in vehicle speed.
A further object of the invention is to provide such an apparatus wherein the
schedule changes the maximum rate of flow of fuel to the engine in discrete
steps that increase as the speed of the vehicle increases.
Yet another object of the invention is to provide such an apparatus wherein the
maximum rate of fuel to the engine is restricted to a preselected value for each
gear being used by the vehicle.
Still another object of the invention is to provide a fuel rate restricting
apparatus which permits limitations on the power available from an engine to be
preselected and outside the control of the operator of the vehicle.
Yet a further object of the invention is to provide an apparatus for restricting
the maximum rate of fuel to an internal combustion engine which results in
increased fuel efficiency and reduced emissions.
Still a further object of the invention is to provide an apparatus for
restricting the maximum rate of fuel to an internal combustion engine wherein
the fumigation of hydrous alcohol fuel into the intake manifold of the engine at
least partially restores the decrease in engine power.
These and other objects of the invention will become apparent from the following
description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial plan view of an internal combustion engine which has been
modified by the apparatus of the present invention.
FIG. 2 is an enlarged detail view of the fuel rate restricting apparatus of FIG.
1;
FIG. 3 is a side view corresponding to FIG. 2 with a part of the governor
control box broken away to show parts interior of the governor control;
FIGS. 4-6 are reduced scale plan views of the apparatus shown in three different
conditions corresponding to the settings for the three gears of the transmission
of the vehicle;
FIG. 7 is a plan view of the governor control box with parts broken away to show
interior parts of the governor control;
FIG. 8 is a plan view of another alternative embodiment wherein the maximum fuel
rate of the mechanical fuel rate control apparatus of the engine is adjusted by
a stepper motor;
FIG. 9 is a graphical representation of vehicle acceleration versus time for a
vehicle unmodified and as modified by an embodiment of the present invention;
<PAGE>
FIG. 10 is a graphical representation of vehicle speed versus time for a vehicle
unmodified and as modified by an embodiment of the present invention;
FIG. 11 is a graphical representation of smoke opacity versus time for a vehicle
unmodified and as modified by an embodiment of the present invention; and
FIGS. 12a and 12b are graphical representations of smoke opacity versus time for
a vehicle unmodified and as modified by an embodiment of the present invention
wherein the vehicles are driven over identical routes.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Illustrated in FIG. 1, generally at 10, is a fuel rate limiting apparatus of the
present invention shown attached to an internal combustion engine 12 of a
vehicle. A throttle apparatus 14 is mounted atop a governor control box 16. A
pair of connecting rods 18a and 18b extend in opposite directions from either
side of the governor control box 16 to where they are pivotally attached at the
outer end portion thereof to one of a pair of fuel injector adjustment racks 20a
and 20b. Axial movement of the connecting rods 18 will thereby adjust the rate
of fuel that will flow through a plurality of fuel injectors 22a-h for supply to
the internal combustion engine 12.
The vehicle includes a foot-operated accelerator (not shown) of the usual type.
Rather than being connected by a mechanical linkage to the throttle apparatus
14, the accelerator operates an air pressure sending unit which is connected to
the throttle apparatus 14 by an air line 24. The pressure in the air line 24
(from 0 to 60 psi) causes a piston 26 of a valve unit 28 to be extended or
retracted in response to changes in position of the foot accelerator. Extension
and retraction of the piston 26 pivots a speed control lever 30 about its
pivotal mount 32 atop the governor control box 16.
The governor control box 16 includes a top plate 34 on which is mounted the
valve unit 28 and the speed control lever 30. Also mounted on the top plate 34
is a stop lever 36, the function of which will be described below. The stop
lever 36 is mounted for pivotal movement on a vertical shaft which extends
through the top plate 34. A return spring 38 received about the vertical shaft
of the stop lever 36 below the top plate 34 biases the stop lever to its off or
idle position. The pivotal mount 32 of the speed control lever 30 also extends
through the top plate 34 and has attached to its bottom end portion a
horizontally extended lever arm 40, the free end portion of which will be moved
in an arc by pivotal movement of the pivotal mount 32 at the speed control lever
30.
<PAGE>
A main operating shaft 42 is mounted for pivotal movement about a vertical axis
inside the governor control box 16. Attached to the upper end portion of the
operating shaft 42 is an operating shaft lever 44 having a pair of lever arms,
stop arm 46 and throttle arm 48. A differential lever 50 is pivotally mounted on
the free end portion of the throttle arm 48. The differential lever 50 includes
a throttle linkage arm 52 that has a slotted or U-shaped end portion within
which is received a connecting member 54 which depends from the horizontally
extended lever arm 40. The differential lever 50 also includes a connecting bar
arm 56 that will be pivoted together with the throttle linkage arm 52 by
movement of the speed control lever 30 as described above. A connecting bar 59
is attached to the free end portion of the connecting bar arm 56 by a pivotal
mount 58 such that pivotal movement of the differential lever 50 will cause
axial movement of the connecting bar 59.
A throttle arm 61 is mounted for pivotal movement about a fixed axis at 63. One
end portion 65 of the throttle arm 61 is pivotally attached to the end of the
connecting bar 59 opposite the connecting bar arm 56. Accordingly, depression of
the accelerator pedal will result in counterclockwise pivotal motion of the
throttle arm 61. The connecting rod 18b is attached to the end portion 65 of the
throttle arm 61 and the other connecting rod 18a is attached to the other end
portion 67 of the throttle arm 61, with the result that the throttle arm 61
adjusts the volume rate of fuel flowing to the engine. The pivot rod 63 extends
upwardly through the top plate 34 and is secured to and mounts for pivotal
movement the stop lever 36. If the stop lever 36 is constrained against
movement, the throttle arm 61 will also be constrained so that no further
adjustment of the volume rate of fuel can be made.
Included in the governor control box is a governor weight assembly 60 mounted on
a horizontal weight shaft 62 which is rotated at a speed corresponding to the
speed of the engine. The governor acts in association with the operating shaft
and stop arm 46 to provide a limit on the degree of motion of the connecting bar
arm 56 in the usual manner by engagement of the connecting bar arm 56 with an
adjusting screw 64 mounted on the free end portion of the stop arm 46.
The top plate 34 of the governor control box 16 ordinarily supports an
adjustable stop which defines the maximum open position for the stop lever 36
and accordingly the maximum fuel rate flow to the engine 12. According to the
present invention, an adjustable stop is provided which is adjustable in
response to a preselected schedule so as to adjust the maximum flow rate of fuel
to the engine 12 in conformance with one or more desired parameters. The
apparatus for providing an adjustable stop includes a central actuator 64 and a
remote slave unit 66. The central actuator 64 is mounted at any position
convenient for the connection to the air line 24 from the foot accelerator pedal
and the remote slave unit 66 is positioned on the top plate 34 of the governor
control box 16 generally in the area in which the fixed stop was located.
The central actuator 64, as illustrated in FIGS. 1-3, consists of a base plate
68 on which is mounted a block 70, an air-actuated extensible and retractable
cylinder 72 and a first and second electrically controlled air cylinder 74 and
76, respectively. A cable 78 interconnects the remote slave unit 66 and the air
cylinder 72 such that extension and retraction of an intercoaxial cable portion
80 by the air cylinder 72 results in extension and retraction of a piston stop
member 82 of the remote slave unit 66. The outer coaxial portion of the cable 78
is fixed to the block 70 and to the outer housing of the remote slave unit 66.
<PAGE>
Mounted in the block 70 and extended in the line of action of the air cylinder
72 are a pair of threaded stop members, first stop member 84 and second stop
member 86. The positions of the end portions of the first and second stop
members 84 and 86 are adjustable to a desired fixed position by a corresponding
lock nut 88a or 88b. As illustrated in FIG. 2, first stop member 84 extends from
the block 70 somewhat closer to the air cylinder 72 than does second stop member
86.
The first and second electrically controlled air cylinders 74 and 76 are
pivotally mounted at 90 and 92, respectively, on the base plate 68 on either
side of the air cylinder 72. The free end of an extensible and retractable
piston 94 of the first electrically controlled air cylinder 74 is pivotally
attached to a first pivot block 96 mounted for pivotal movement at 98 on the
base plate 68. A roller 100 is mounted for rotational movement on the first
pivot block 96 in a similar fashion, the free end portion of a piston 102 of the
second electrically controlled air cylinder 76 is pivotally mounted to a second
pivot block 104 which is pivotally mounted at 106 to the base plate 68. The
second pivot block 104 also supports for rotational movement a second roller
108.
Each of the air cylinders 72-76 are connected to the air line 24. The air
cylinders 74 and 76 are also connected by means of electrical cable 110 and 112,
respectively, to a transponder connected to the three-speed transmission (not
shown) of the vehicle. Accordingly, the air cylinder 72 extends and retracts in
response to the position of the accelerator pedal such that upon full extension,
as illustrated in FIG. 4 wherein a plate 114 attached to the free end portion of
piston abuts the block 70, corresponds to the minimum or idle position of the
accelerator pedal. In this position, the intercoaxial cable 80 is at its maximum
extended position from the remote unit 66. As the accelerator pedal is
depressed, the linear actuator 72 will retract the piston and plate 114 until it
comes into contact with either of the rollers 100 or 108. If the transmission is
in first gear, corresponding to FIG. 5, the first electrically controlled air
cylinder 74 will be extended until the roller 100 comes into contact with the
first stop member 84. Contact of the plate member 114 with the first roller 100
will stop retraction of the air cylinder 72 whether or not the foot accelerator
pedal has been depressed beyond that corresponding location. This will result in
retraction of the intercoaxial cable 80 so as to permit additional
counterclockwise movement of the stop lever 36.
If instead the transmission of the vehicle is in second gear, the first
electrically controlled air cylinder 74 will be retracted and the second
electrically controlled air cylinder 76 will be extended until the roller 108
comes into contact with the second stop member 86, as illustrated in FIG. 6. In
this condition, depression of the foot accelerator will retract the air cylinder
72 until the plate 114 comes into contact with the roller 108. As before, the
extension of the intercoaxial cable 80 beyond the remote slave unit 66 will be
adjusted to provide a stop position for the stop lever 36.
Finally, if the transmission of the vehicle is in the third gear, both
electrically controlled air cylinders 74 and 76 will be fully retracted, as
illustrated in FIG. 4, so that full depression of the accelerator pedal will
<PAGE>
allow retraction of the air cylinder 72 until the plate member 114 comes into
contact with the rollers 100 and 108. The central actuator has been constructed
and adjusted so that this position allows the full rate of fuel delivery to the
engine as was permitted by the unmodified engine.
The present invention is advantageously employed on an internal combustion
engine modified as described in U.S. Pat. No. 4,958,598 which is incorporated
herein by this reference. The '598 patent teaches the use of a low proof hydrous
alcohol fuel used to supplement the primary fuel of the engine. The FIGS. 9-12
represent graphically data taken from a General Motors RTS 30-foot bus having a
8V71 Detroit Diesel non-turbocharged engine modified with the apparatus of the
present invention as disclosed in FIGS. 1-6 of this application and the
apparatus of the '598 patent. The modified bus was tested for acceleration and
smoke opacity over typical urban route conditions and these data are compared
with data taken from the unmodified bus under identical conditions.
As an alternative embodiment, a stepper motor 120 is mounted on the top plate 34
of the governor control box 16 (FIG. 8). The stepper motor 120 has a screw 122
that is extensible and retractable in fine, exact and reproducible increments.
The end 124 of the screw 122 serves as a stop for the stop lever 36 in the same
fashion as did the end of the cable 80 (FIGS. 2, 4-6) in the first embodiment.
The stepper motor 120 is electrically controlled and may be conveniently
operated by a microprocessor that is connected to a plurality of tranducers for
sensing various operating conditions, such as vehicle velocity, pitch or incline
of the vehicle, and wind direction and speed. A potentiometer adjusted by the
accelerator pedal is also connected to the microprocessor. The stepper motor 120
is capable of adjusting the position of the stop lever 36 in approximately 500
substantially equally spaced divisions to permit a much greater degree of
flexibility in the limiting of maximum fuel flow rate to the engine under a
plurality of operating conditions.
In FIG. 9, acceleration of the two vehicles over time is represented, showing
that some decrease in acceleration was experienced. This decrease, however, was
not so noticeable as to be the subject of negative comment by the drivers of the
vehicles.
Velocity of the two vehicles over time is illustrated in FIG. 10. Again, some
reduction in performance was observed, i.e., a reduction in average speed (over
a distance of 1452 feet with an average grade of 1.55 percent) of from 26.5
m.p.h. to 23.5 m.p.h. However, a primary fuel savings of 17.2 percent was
realized.
The opacity of exhaust emitted by the two vehicles was measured over the
acceleration sequence of FIG. 9 by using a Celisco opacity meter, model 200, as
shown in FIG. 11. The modified vehicle had substantially reduced opacity of the
emission particularly during the early stages of the acceleration sequence.
Smoke opacity measurements over a typical urban route of the unmodified vehicle
(FIG. 12a) and the modified vehicle (FIG. 12b) were measured. The reduction in
emission opacity is marked.
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