Throttle modulation mechanism

A throttle modulation mechanism (10) disposed between a throttle pedal (28) and a fuel control device (12) varies speed and torque of an unshown engine. Mechanism (10) is operable during shifting modes of an unshown transmission driven by the engine to dip and boost fuel delivery to the engine for synchronizing the transmission and/or reducing shifting shocks. Mechanism (10), which is controlled by a transmission logic (14), includes first and second levers (16, 20) interconnected for slaved movement by a torsion spring and fluid actuated cylinders (38, 40) which respectively dip and boost the throttle in response to logic signals applied to solenoid valves (50, 64). A transducer (24), mechanically connected to first lever (16), provides an electrical signal representative of throttle pedal position. Torsion spring (22) includes ends (22b, 22c) preloaded toward each other and clamping levers (16, 20 or 106) into a predetermined relationship.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a mechanism for automatically modulating 
fuel delivery to an engine. More specifically, the present invention 
relates to such a mechanism for synchronizing and/or reducing shifting 
shocks of a transmission. 
2. Description of the Prior Art 
It has been previously proposed to automatically modulate or vary the speed 
of an engine during shifting modes of a transmission in an effort to 
simulate what is done by an experienced driver during manual shifting. For 
example, U.S. Pat. No. 3,736,806 proposes increasing fuel delivery to an 
engine during manual shifting of a mechanical transmission; U.S. Pat. No. 
3,834,499 proposes both increasing and decreasing fuel delivery to an 
engine during automatic shifting of a mechanical transmission; and U.S. 
Pat. No. 4,226,141 proposes decreasing fuel delivery to an engine during 
automatic shifting of a transmission to facilitate synchronization of the 
transmission and to reduce shifting shocks. 
The prior art mechanisms for modulating engine speed during shifting modes 
of a transmission have had several disadvantages. Most have been on/off 
type mechanisms which have not provided smooth, precise change in engine 
speed and torque and, therefore, have provided less than optimum 
synchronizing and shift shock results. Some have been incorporated 
directly into fuel control devices and therefore have required complex and 
costly redesign of the fuel control devices. Some have operated directly 
on throttle pedal linkages with resulting mechanical feedback o physical 
movement of the throttle pedal. This feedback or movement, which is 
noticed by the operator, is disagreeable and interferes with proper and 
effective control of the vehicle. 
Further, with respect to optimum synchronizing and shift shock, the prior 
art mechanisms have not readily provided the many different precise 
degrees of fuel delivery change necessary during shifting modes of a 
transmission. For example, precisely regulated, ramped, incremental 
increases and decreases of fuel delivery can greatly reduce shifting 
shocks felt by a vehicle operator, reduce torsional oscillations in the 
vehicle drivetrain, reduce synchronizing time, reduce energy consumed by 
synchronizing devices, and reduce impulse forces on jaw clutches. 
Further with respect to mechanical feedback or physical movement of the 
throttle pedal, even though a modulation mechanism may not physically move 
the throttle pedal during throttle modulation, the mechanism may cause 
objectionable force changes on the throttle pedal if the spring biasing 
the throttle system toward idle is not properly positioned and 
proportioned. These force changes, though not as disagreeable as physical 
movement of the throttle pedal, are nevertheless distracting to a vehicle 
operator. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a mechanism for controlling fuel 
delivery to a prime mover independent of throttle pedal position during 
shifting of a transmission driven by the prime mover. 
Another object of this invention is to provide such a mechanism for 
controlling shifting shocks. 
Another object of this invention is to provide such a mechanism for 
effecting synchronism in an automatic mechanical transmission. 
According to a feature of the invention, the mechanism of the present 
invention is adapted to be interposed between an engine throttle pedal and 
an engine fuel control device such as throttle valve or a fuel injection 
device. The mechanism comprises first and second members mounted for 
relative movement and respectively adapted to be connected to the throttle 
pedal and the fuel control device for slaved movement therewith; resilient 
means clamping the members into a predetermined positional relationship 
with a preloaded, resilient force, the resilient means operative to 
maintain the predetermined relationship in response to movement of the 
throttle pedal during nonshifting modes of the transmission and operative 
to allow relative to-and-fro movement of the members from the 
predetermined relationship during shifting modes of the transmission 
clamping the members into a predetermined positional relationship with a 
preloaded, resilient force, the resilient means operative to maintain the 
predetermined relationship in response to movement of the throttle pedal 
during nonshifting modes of the transmission and operative to allow 
relative to-and-fro movement of the members from the predetermined 
relationship during shifting modes of the transmission; and means for 
moving the second member independent of the throttle pedal position during 
shifting modes of the transmission. 
According to another feature of the invention, the mechanism, as adapted in 
the previous feature, includes first and second members mounted for 
pivotal movement about a common axis and respectively adapted to be 
connected to the throttle pedal and the fuel control device for slaved 
movement therewith; a torsion spring clamping the members into a 
predetermined positional relationship with a preloaded, resilient force, 
the resilient means operative to maintain the predetermined relationship 
in response to movement of the throttle pedal during nonshifting modes of 
the transmission and operative to allow relative to-and-fro movement of 
the members from the predetermined relationship during shifting modes of 
the transmission clamping the members into a predetermined positional 
relationship with a preloaded, resilient force, the resilient means 
operative to maintain the predetermined relationship in response to 
movement of the throttle pedal during nonshifting modes of the 
transmission and operative to allow relative to-and-fro movement of the 
members from the predetermined relationship during shifting modes of the 
transmission; and means for rotating the second member independent of the 
throttle pedal position during shifting modes of the transmission.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 schematically shows a two-lever throttle modulation mechanism 10 for 
automatically decreasing and increasing fuel delivery from a fuel control 
device 12 to an unshown prime mover in response to signals from a 
transmission logic 14 during shifting modes of an unshown transmission 
driven by the prime mover. Mechanism 10 is contemplated for use in a 
wheeled vehicle such as a truck. The prime mover may be of any adaptable 
type, e.g. the prime mover may be an engine of the Otto or diesel cycle 
type. The transmission may also be of any multiple ratio type, e.g., a 
manually shifted transmission employing positive or jaw-type clutches to 
effect ratio changes, an automatically shifted transmission employing 
friction clutches to effect ratio changes, or an automatically shifted 
transmission employing positive clutches to effect ratio changes. 
Mechanism 10 is contemplated for use with this latter type of 
transmission, which is often referred to as an automatic mechanical 
transmission. Such a transmission and logic system for controlling 
shifting is disclosed in U.S. Pat. No. 4,361,060 which issued Nov. 30, 
1982. U.S. Pat. No. 4,361,060 is incorporated herein by reference. 
Mechanism 10 includes a first lever or member 16 fixed at one end 16a (see 
mechanism 100 of FIG. 3) to a shaft 18 mounted for rotation or oscillatory 
movement about its longitudinal axis, a second lever or member 20 mounted 
for rotation or oscillatory movement about the axis of shaft 18 and 
relative to the shaft and first lever 16, a torsion spring 22 (See FIGS. 
2-6), and a transducer in the form of a potentiometer or pot 24 for 
providing an electrical signal representative of the position of first 
lever 16. The electrical signal is fed to logic 14 via a wire 25. First 
lever 16 is pivotally connected at its other end 16b to a linkage 
mechanism 26 moved in direct response to the position of an 
operator-controlled throttle pedal 28. Hence, pot 24 provides a signal 
representative of throttle pedal position. Second lever 20 is connected at 
its upper end to 20a the left end of a link 30 by a pivot connection. The 
lower end 20b of lever 20 is disposed between two actuators. The right end 
of link 30 is pivotally connected to a lever 34 which rotates a shaft 35 
to vary fuel flow to the engine in response to rotation from the idle 
throttle position shown in FIG. 1 to the full or wide-open throttle 
position to be described hereinafter with respect to embodiment 100 in 
FIG. 2. First lever 16, link 26, and throttle pedal 28 are biased toward 
the idle throttle position by a spring 36. Second lever 20, link 30, and 
lever 34 are biased toward the idle throttle position by spring 36 via 
torsion spring 22 which is shown in FIGS. 2-6. 
Mechanism 10 further includes throttle dip cylinder or actuator 38 to 
rotate second lever 20 clockwise independent of first lever 16 and a 
throttle boost cylinder or actuator 40 to rotate second lever 20 
counterclockwise independent of first lever 16. Actuator 38 includes a 
cylinder housing 42, a piston 44, a piston rod 46 fixed to the piston, and 
a spring 48 biasing the piston to the right. Piston 44 is moved to the 
left by pressurized fluid controlled by an electrically operated valve 50. 
Valve 50 is connected to an unshown source of pressurized fluid, such as 
air, by a conduit 52 and to actuator 38 by a conduit 54. Valve 50 is 
electrically connected to logic 14 via a wire 56. Boost actuator 40 
includes a cylinder housing 58, a piston 60, a piston rod 61 fixed to the 
piston, and a spring 62 biasing the piston to the left. A valve 64, 
substantially identical to valve 50, is connected to the source of 
pressurized fluid by a conduit 66 and to actuator 40 via a conduit 68. 
Valve 64 is electrically connected to logic 14 via a wire 70. 
During nonshifting modes of the transmission, the pistons of the dip and 
boost cylinders remain in the positions shown in FIG. 1, whereby complete 
control of fuel delivery to the engine is a function of throttle pedal 
position due to the torsion spring interconnection of first and second 
levers 16 and 20. In FIG. 1, throttle pedal 28 and fuel control lever 34 
are in the idle position with end 20b of lever 20 adjacent piston rod 61. 
As throttle pedal 28 is moved toward the wide-open throttle position, 
levers 16 and 20 freely rotate counterclockwise and at the wide-open 
throttle position end 20b is adjacent piston rod 46. During shifting modes 
of the transmission, as shown hereinafter, logic 14 energizes valves 50 
and 64 in predetermined sequences to change the position of second lever 
20 with respect to first lever 16 without actual movement of the throttle 
pedal due to the torsion spring connection between the first and second 
levers. 
Valves 50, 64 may be of the nonpressure regulating type which either vent 
or apply full fluid pressure to the cylinder in response to the presence 
or absence of electrical signals from logic 14, whereby the cylinder 
pistons are either fully actuated or unactuated. Valves 50 and 64 are 
preferably of the pressure regulating type which control the pressure of 
the fluid to an from the cylinders, thereby controlling the piston 
position and rate of movement. Further, valves 50 and 60 may each be 
replaced by two or more valves controlled by the logic. Such valves and 
logics for controlling them are well-known, e.g., the valves may be 
responsive to amplitude modulated or duty-cycle modulated signals from the 
logic. One valve could be energized to vent its associated cylinder and 
the other to port fluid pressure to its associated cylinder. 
Looking now at FIGS. 2-3 therein, the throttle modulation mechanism is 
shown in greater detail with components identical to components in FIG. 1 
bearing the same numerals. The mechanism 10 includes a housing assembly 
100 having a base member 102 with slotted opening 102a receiving screws 
103 for securing the housing assembly on an unshown fuel control device 
and a plate member 104, the first lever 16 welded at its lower end 16a to 
shaft 18, a second lever 106 in lieu of the second lever 20 in FIG. 1, the 
torsion spring 22, throttle pedal position pot 24 secured to plate member 
104 by screws 105 and actuators 38, 40 with piston rods 46, 61 protruding 
therefrom. Lever 16 is biased toward the idle throttle position by spring 
36 as shown in FIG. 1. 
Lever 16 is pivotally connectable at its upper end 16b to link 26 and is 
moveable in the embodiment of FIG. 1 and FIGS. 2-6 between idle throttle, 
wide-open throttle, and over-throttle positions A, B, and C, respectively. 
Movement between positions A and B varies fuel flow to the engine. 
Movement between positions B and C protects shaft 35 of fuel control 
device 12 when the throttle pedal is moved beyond the wide-open throttle 
position. Movement between positions B and C may be used to operate an 
unshown kickdown switch for the transmission. Base member 100 of the 
housing assembly 102 includes a stepped bore 102b housing two ball bearing 
108, 110 assemblies disposed therein for rotatably supporting shaft 18 and 
two downwardly extending flanges 102c, 102d having threaded bores disposed 
along a common axis and receiving threaded ends 38a, 40a for rigidly 
securing actuator 38, 40 to the housing assembly. The right end of shaft 
18 is welded to the lower end 16b of lever 16. Flange 102d, which is 
hidden in FIG. 2 by the unbroken away portion of plate member 104, is 
visable in FIG. 3. A stepped shoulder or flange 18a and a snap ring 112 
prevent axial movement of shaft 18 in the bearings. Plate member 104 is 
secured to base member 102 by a plurality of screws 114 and includes a 
double stepped bore 104a, 104b defining a flange portion 104c 
therebetween. Bore 104a receives the outer race of bearing 108, flange 
portion retains the bearing against axial movement relative to the housing 
assembly, and bore 104b receives the back portion of pot 24. The back 
portion of pot 24 is open to receive an extension 18b of shaft 18 which 
drives a wiper 116 within via a pin 118. 
Lever 106 includes upper and lower arm portions 106a, 106b welded to a 
central hub 106c having an opening 106d for receiving a rotatable shaft 
such as shaft 35 from fuel control device 12. Unshown stops within fuel 
control device 12 limit rotation of shaft 35 between idle and wide-open 
throttle. Shaft 35 is secured in the opening by a screw 120. Housing 
assembly is aligned so that shafts 18 and 35 lie substantially along a 
common axis arm portion 106b of lever 106 includes a shoulder bolt 122 
having an unthreaded portion 122a supporting a needle bearing 124 and a 
threaded portion 122b extending through an opening in the arm and 
threadably received by a bore 126a in a drum 126 supporting coils 22a of 
the torsion spring 22. Upper arm portion 106a includes a right angle tab 
portion 106e disposed radially inward from a right angle tab 16c welded to 
lever 16. Levers 16 and 106 are resiliently clamped into a predetermined 
positional relationship by torsion spring arms 22b and 22c. The arms are 
preloaded toward each other with a force suffice to maintain the 
positional relationship in response to movement of arm 16 by throttle 
pedal 28 during nonshifting modes of the unshown transmission. Further, 
the preload force is preferably sufficiently less than the force of spring 
36 in FIG. 1 so that movement lever of 106 by actuators 38, 40 during a 
shifting mode of the transmission is relatively unnoticeable by a vehicle 
operator having his foot on the throttle pedal. 
FIGS. 2-4 show levers 16 and 106 in the wide-open throttle position with 
actuators 38, 40 in their unactuated positions. FIG. 5 shows lever 16 in 
the wide-open throttle position with lever 106 moved to the idle or 
throttle dip position by dip actuator 38. FIG. 6 shows lever 16 in the 
idle throttle position with lever 106 moved to the wide-open or throttle 
boost position by boost actuator 40. 
A stop 128, supported by a partially shown portion of base member 104, 
limits or sets the position of lever 16 when the throttle pedal is in the 
idle throttle position. When the throttle pedal is in the idle throttle 
position and the boost actuator or both actuators are in the unactuated 
positions, the unshown stops within fuel control device 12 set the 
position of lever 106 at the position shown in FIG. 5 and the stop 128 
sets the position of lever 16 at the position shown in FIG. 6. When the 
levers are in these two positions, lever 16 is a degree or two clockwise 
beyond lever 106, whereby initial movement of the throttle pedal and lever 
16 from the idle throttle pedal position will not move lever 106 and shaft 
35. This dead or lost motion band between the levers actuates an unshown 
switch which provides an electrical signal informing logic 14 that the 
vehicle operator's foot is on the throttle pedal. 
Operation 
To describe operation, it will be assumed that mechanism 10 is in a wheeled 
vehicle in combination with an automatic mechanical transmission having 
jaw-type clutches for engaging and disengaging step ratio gears in the 
transmission and a friction type master clutch interposed between the 
prime mover and the transmission. The jaw and master clutches are 
controlled by logic 14. Further, logic 14 maintains the master clutch 
disengaged when the vehicle is at rest and the unshown switch actuated by 
lever 16 indicates that the vehicle operator's foot is off the throttle 
pedal. The unshown switch may be incorporated in pot 24 in a well-known 
manner with an electrical signal therefrom supplied to logic 14 by wire 
25. The transmission may further include devices to assist synchronization 
of the jaw clutches, e.g., the jaw clutches may each include a 
synchronizer which effects upshift and downshift synchronization or, 
retarder and accelerator devices which respectively effect upshift and 
downshift synchronizing of all of the ratios. The retarder may be a brake 
connected to the transmission input shaft, and the accelerator may be a 
clutch operative to connect the input shaft with a faster rotating member. 
Such retarder and accelerator devices are well-known in the art and are 
readily made responsive to signals from a logic. Further, size, wear, and 
effectiveness of all of these devices is enhanced by mechanism 10 since 
the amount of torque they would often have be handled is decreased by 
throttle modulation. 
Assuming now that the transmission shift selector is in a forward drive 
position with the throttle pedal in the idle position and the vehicle at 
rest, the master clutch is therefore disengaged, and a starting ratio gear 
is engaged. When the throttle pedal is depressed, the master clutch is 
engaged at a rate determined by throttle pedal position and other known 
parameters. When the vehicle reaches a speed, determined by throttle 
position and other parameters, logic 14 initiates an upshift mode; at this 
time the throttle pedal may be at any position between idle and up to an 
including wide-open throttle as shown in FIG. 3. The upshift mode may 
comprise several different sequences to effect the upshift. Herein is one 
sequence: logic 14 sends a throttle dip signal to valve 50 via wire 56 to 
dip the throttle or decrease fuel delivery to the engine, thereby reducing 
engine torque in the vehicle drivetrain and suspension system at a 
controlled rate prior to disengagement of the master clutch. Concurrent or 
substantially concurrent with the throttle dip signal, logic 14 initiates 
disengagement of the then-engaged jaw clutch, which will not normally move 
to the disengaged position until the driveline torque across the jaws 
diminishes. The logic then initiates disengagement of the master clutch if 
the transmission includes a retarder, such as a brake, to reduce input 
shaft speed for synchronizing the jaw clutch to be engaged for the next 
upshift ratio. As synchronization is reached, the logic initiates 
reengagement of the jaw clutch and then engagement of the master clutch at 
a controlled rate, and then throttle boost by venting actuator 38 and/or 
pressurizing actuator 40 to control the rate of engine speed and torque 
rise commensurate with a smooth shift. Further upshifts are substantially 
the same. 
Downshifts differ principally in that they require an increase in input 
shaft speed to effect synchronization. When logic 14 senses the need for a 
downshift, a throttle dip signal is sent to valve 50 via wire 56 as during 
an upshift. Concurrent or substantially concurrent with the throttle dip 
signal, logic 14 initiates disengagement of the then-engaged jaw clutch 
which will not normally move to the disengaged position until the 
driveline torque across the jaws diminishes. The logic then initiates 
disengagement of the master clutch. If the transmission includes an 
accelerator device, as previously mentioned, the device increases the 
input shaft speed to synchronize the jaw clutch to be engaged while the 
master clutch remains disengaged; as synchronization is reached, the logic 
initiates engagement of the jaw clutch and then engagement of the master 
clutch. If the transmission does not include such a device, logic 14 
initates engagement of the master clutch and then throttle boost to effect 
synchronization by sending a boost signal to valve 64 via wire 70, then 
disengagement of the master clutch as synchronization is reached and 
engagement of the jaw clutch, and then reengagement of the master clutch 
at a controlled rate. This engagement, disengagement, and reengagement of 
the master clutch during the downshift sequence is the well-known double 
clutch procedure long practiced by operators of manually shifted 
transmissions. 
One embodiment of the invention has been disclosed for illustrative 
purposes. Many variations and modifications of the disclosed embodiment 
are believed to be within the spirit of the invention. The following 
claims are intended to cover the inventive portions of the invention and 
variations and modifications within the spirit of the disclosed invention.