192 clutches and power-stop control – Clutches – Torque responsive
Reexamination Certificate
2000-04-06
2002-06-04
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Torque responsive
C062S133000, C192S08200T, C192S084100, C192S1030FA
Reexamination Certificate
active
06397995
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method for controlling a clutch. In particular, the invention relates to a method for controlling a clutch for an engine-powered system, such as an air conditioner system, to minimize a vehicle vibration due to a torque pulse generated by actuation of the clutch.
BACKGROUND OF THE INVENTION
Air conditioner systems have long been utilized in automotive vehicles to enhance the comfort of vehicle occupants. Referring to
FIG. 1
, an automotive vehicle
10
is illustrated. Referring to
FIG. 2
, the vehicle
10
may include a conventional air conditioner system
11
that circulates a cooling medium. The air conditioner system
11
includes a compressor
12
, a condenser
14
, an expansion valve
16
, an evaporator
18
, and a pressure sensor
20
. Referring to
FIG. 1
, the compressor
12
is mounted on an automotive engine
22
and is powered by the engine
22
via a driven belt
40
, a pulley
36
and a clutch
24
. The clutch
24
has a first state torsionally engaged with the compressor
12
and a second state disengaged from the compressor
12
. When the clutch
24
is torsionally engaged with the compressor
12
, the compressor
12
is driven by the belt
40
. The compressor
12
compresses the cooling medium and delivers the cooling medium to the condenser
14
, which transfers heat from the cooling medium. The condenser
14
delivers the cooling medium to the expansion valve
16
that expands the cooling medium into a gaseous form. The expansion valve
16
delivers the cooling medium to the evaporator
18
which transfers heat from air in a vehicle passenger compartment (not shown) to the cooling medium—to thereby cool the interior of the passenger compartment.
Referring to
FIG. 3A
, the engine
22
for powering the air conditioner system
11
is illustrated. The engine
22
is resting on engine mounts
28
,
30
of the vehicle
10
and has a longitudinally extending torque roll axis
32
. Referring to
FIGS. 2 and 3A
, the engine
22
includes a crankshaft
34
, pulleys
36
,
38
, a belt
40
, the clutch
24
, and the compressor
12
. The remaining components of the engine
22
have been removed for clarity of illustration. Referring to
FIGS. 3A and 3B
, during operation of the engine
22
, the engine
22
rocks back and forth about the torque roll axis
32
at a natural frequency. The rocking motion of the engine
22
is generally called an oscillating roll movement. The natural frequency of the oscillating roll movement will vary with different engines and powertrains, but remains relatively constant at different engine speeds for a given engine and powertrain.
FIGS. 3A and 3B
illustrate the two extremes of the oscillating roll movement of the engine
22
.
Referring to
FIG. 3A
, during operation of the engine
22
, an external reaction torque is applied to the engine
22
by the powertrain (not shown) of the vehicle
10
—in response to the torque applied by the engine
22
to the powertrain. As illustrated, the direction of the external reaction torque (counter-clockwise in
FIG. 3A
) is opposite the direction of the crankshaft rotation (clockwise in FIG.
3
A).
The engagement of the clutch
24
to drive the compressor
12
results in an almost instantaneous reduction in the engine torque (not shown) and thus an almost instantaneous reduction in the external reaction torque. This instantaneous reduction in the external reaction torque is effectively a torque pulse in a direction counter to the direction of the external reaction torque (clockwise in FIG.
3
A). As a result of the torque pulse, the vehicle occupants may feel an undesirable vibration during the engagement of the clutch
24
.
Similarly, the disengagement of the clutch
24
results in an almost instantaneous increase in the engine torque (not shown) and thus an almost instantaneous increase in the external reaction torque. This instantaneous increase in the external reaction torque is effectively a torque pulse in the same direction as the external reaction torque (counter-clockwise in FIG.
3
A). Similarly, as a result of the torque pulse, the vehicle occupants may feel an undesirable vibration during the disengagement of the clutch
24
.
There is thus a need for a method of controlling a clutch for an engine-powered system in an automotive vehicle that minimizes or reduces one of more of the above-mentioned deficiencies.
SUMMARY OF THE INVENTION
The present invention provides a method of controlling a clutch for an engine-powered system (such as an air conditioner system) in an automotive vehicle to reduce and/or minimize a vehicle vibration due to a torque pulse generated by engaging and disengaging the clutch.
Referring to
FIG. 3A
, it has been determined that the best time in the natural oscillating roll movement of an engine to engage a clutch—and to absorb a corresponding torque pulse (in a clockwise direction in FIG.
3
A)—is when the engine is moving at a maximum velocity and therefore momentum in a direction counter to the direction of the torque pulse (in a counter-clockwise direction in FIG.
3
A). Thus the optimum time to engage the clutch is at the mid-travel position of the roll (i.e., position of maximum velocity) when the engine is moving in a counter-clockwise direction about the torque roll axis. Since there may be a small delay from the time the clutch is energized to the time the clutch actually engages a compressor, the optimum time to energize the clutch may be slightly before the mid-travel position.
Similarly, it has been determined that the best time in the natural oscillating roll movement of the engine to disengage the clutch—and to absorb a corresponding torque pulse (in a counter-clockwise direction in FIG.
3
A)—is when the engine is moving about at a maximum velocity and therefore momentum in a direction counter to the direction of the torque pulse (in the clockwise direction in FIG.
3
A). Thus the optimum time to disengage the clutch is at the mid-travel position of the roll (i.e., position of maximum velocity) when the engine is moving in a clockwise direction about the torque roll axis. Since there may be a small delay from the time the clutch is de-energized to the time the clutch actually disengages, the optimum time to de-energize the clutch may be slightly before the mid-travel position.
A method for controlling a clutch for an engine-powered system (such as an air conditioner system) in an automotive vehicle, includes the steps of generating an engine roll signal responsive to an oscillating roll movement of an engine about a torque roll axis. The method further includes the step of determining a direction of the oscillating roll movement utilizing the engine roll signal. Finally, the method includes the step of actuating the clutch responsive to an operational parameter of the engine-powered system and the direction of said oscillating roll movement. The operational parameter may be a pressure measurement in the air conditioner system.
An automotive vehicle in accordance with the present invention includes a clutch having a first state torsionally engaged with a component of an engine-powered system and a second state disengaged from the component of the engine-powered system. The vehicle further includes a first sensor generating a first signal indicative of an operational parameter of the engine-powered system. The vehicle further includes a second sensor generating a second signal responsive to the oscillating roll movement of the engine indicative of a direction of the oscillating roll movement. Finally, the vehicle includes a controller for actuating the clutch responsive to the operational parameter of the engine-powered system and to the direction of the oscillating roll movement. The engine-powered system may comprise an air conditioner system with a compressor driven by the engine.
A method and an automotive vehicle in accordance with the present invention represent a significant improvement over conventional methods and vehicles. In particular, the method and vehicle minimizes the vibration during t
Ellsworth Eric D.
Meckstroth Richard John
LandOfFree
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