US2010218738A1PendingUtilityA1
Non-synchronous belt driven camshaft phase shift device
Est. expiryOct 9, 2027(~1.2 yrs left)· nominal 20-yr term from priority
F01L 1/024F01L 1/02
43
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Claims
Abstract
A non-synchronous camshaft phasing device 46 for use with an internal combustion engine E. The internal combustion engine E includes an engine control unit ECU, a camshaft 42 and a crankshaft 12. The non-synchronous phasing device 46 is located between the crankshaft 12 and the camshaft 42 for controlling a phase shift angle between the camshaft 42 and the crankshaft 12. The phasing device 46 comprises an input shaft 36 coupled to the crankshaft 12 via a non-synchronous belt 40. The phasing device 46 also comprises an output shaft 42 coupled to the camshaft 44; a planetary gear train 48 co-axially aligned around and coupled with the input shaft 36 and the output shaft 42; and an motor 50 coupled to the planetary gear train 48 by a carrier 56. A controller operatively connects to the engine control unit ECU, wherein the controller is configured to receive engine operating signals generated by the engine control unit ECU and to receive signals from position sensors 51 coupled to the input shaft 36 and to the output shaft 42. In response to the signals, the controller generates and sends a torque command signal to the motor 50 to command the motor 50 to control the planetary gear train 48 through the carrier 56 to adjust the phase shift angle between the camshaft and the crankshaft 12.
Claims
exact text as granted — not AI-modified1 . In an internal combustion engine having an engine control unit, a crankshaft and a camshaft and a phase shift device coupling the crankshaft and the camshaft for controlling a phase shift angle between the crankshaft and the camshaft, the phase shift device comprising:
a non-synchronous belt operatively connected to the crankshaft; an input shaft operatively connected to the non-synchronous belt, the input shaft having a first sun gear coupled to an end of the input shaft; an output shaft coupled to the camshaft, the output shaft having a second sun gear coupled to an end of the output shaft; a planetary gear train co-axially aligned around the first sun gear and the second sun gear, the planetary gear train includes a carrier and a planet gear having a first gear end and a second gear end that engage the first sun gear and the second sun gear, respectively, and are united to rotate about a common axis through a first bearing and a second bearing of the carrier; a motor operatively connected to the carrier; and a controller operatively connected to the engine control unit and the motor, the controller being configured to receive engine operating signals generated by the engine control unit and to receive signals from position sensors coupled to the input shaft and to the output shaft and in response thereto being configured to generate and send a command signal to the motor to command the motor to control the planetary gear train through the carrier to adjust the phase shift angle between the camshaft and the crankshaft.
2 . The phase device of claim 1 further comprising an input shaft pulley connected to the input shaft at an end of the input shaft opposite the first sun gear and comprises a crankshaft pulley connected to the crankshaft wherein the non-synchronous belt operatively connects to the crankshaft pulley and the input shaft pulley.
3 . The phase device of claim 2 wherein a creep rate of the non-synchronous belt is denoted “γ”; a ratio of pitch diameter of the crankshaft pulley to pitch diameter of the input shaft pulley is denoted “ψ”; and a ratio of the angular velocity of the crankshaft to the angular velocity of the input shaft is denoted “φ” which is characterized by the equation
ϕ
=
ψ
1
-
γ
·
4 . The phase device of claim 3 wherein a gear ratio denoted “i b ” of the planetary gear train is characterized by the equation
i
b
=
N
S
1
·
N
P
2
N
S
2
·
N
P
1
where
N S1 , N S2 =number of teeth for the first and second sun gears respectively; and
N P1 , N P2 =number of teeth for the first and second gear ends respectively.
5 . The phase device of claim 4 wherein the controller commands the motor to control the planetary gear train such that the angular speed of the carrier ω C is controlled to maintain a relationship with the angular speed of the input shaft w S1 according to the equation:
ω
C
ω
S
1
=
2
-
2
i
b
ϕ
-
2
i
b
,
6 . The phase device of claim 4 wherein the controller commands the motor to control the planetary gear train such that the angular speed of the carrier ω C is controlled to maintain a relationship with the angular speed of the output shaft ω S2 according to the equation:
ω
C
ω
S
2
=
ϕ
-
2
i
b
ϕ
-
ϕ
·
i
b
·
7 . The phase device of claim 3 wherein the planetary gear comprises a first planet gear and a second planet gear such that the first planet gear meshes with the first sun gear and the second planet gear meshes with the second sun gear.
8 . The phase device of claim 7 wherein a gear ratio denoted “i b ” of the planetary gear train is characterized by the equation
i
b
=
N
S
1
·
N
P
2
N
S
2
·
N
P
1
where
N S1 , N S2 =number of teeth for the first and second sun gears respectively; and
N P1 , N P2 =number of teeth for the first and second planet gears respectively.
9 . The phase device of claim 8 wherein the controller commands the motor to control the planetary gear train such that the angular speed of the carrier ω C is controlled to maintain a relationship with the angular speed of the input shaft Ω S1 according to the equation:
ω
C
ω
S
1
=
2
-
2
i
b
ϕ
-
2
i
b
10 . The phase device of claim 2 wherein angular speed ratio of the crankshaft to the input shaft is denoted “ω” and is related to the creep rate though the equation
ϕ
=
2
(
1
-
γ
0
)
1
-
γ
where
γ=the effective creep rate, defined as a percentage pitch line velocity loss with respect to pitch line velocity of the crankshaft pulley; and
γ 0 =a predetermined nominal creep rate of the non-synchronous belt.
11 . The phasing device of claim 1 wherein the controller comprises a feed forward block that is configured to process anticipated torque disturbances applied to the internal combustion engine.
12 . The phase device of claim 11 wherein an output of the feed forward branch T ffwd is determined according to the equation
T ffwd =T rq — static +T rq — friciton =(1 −i b )· T cam +sgn( v )· f ( T cam ) where T rq — static is calculated from a frictionless static equilibrium condition of the three-branch gear drive; T rq — friction is a component required to overcome frictional torque for current camshaft torque load; T cam =the camshaft torque load; and f(T cam )=magnitude of T rq — friction .
13 . In an internal combustion engine, a method of controlling a phase shift angle between a camshaft and a crankshaft, the method comprising:
connecting a non-synchronous belt to the crankshaft and to an input shaft having a first sun gear end coupled to an end of the input shaft; aligning a planetary gear train around the input shaft and around an output shaft coupled to the camshaft, the output shaft having a second sun gear coupled to an end of the output shaft; meshing a first planet gear of the planetary gear train with the first sun gear and meshing a second planet gear of the planetary gear train with the second sun gear, the first and second planet gears being united to rotate about a common axis through a carrier of the planetary gear train; operatively connecting a motor to the carrier; and commanding the motor to control the planetary gear train through the carrier to adjust the phase shift angle between the camshaft and the crankshaft.
14 . The method of claim 13 wherein controlling the motor comprises commanding the motor to control the planetary gear train such that the angular speed of the carrier ωw C is controlled to maintain a relationship with the angular speed of the input shaft ω S1 according to the equation:
ω
C
ω
S
1
=
2
-
2
i
b
ϕ
-
2
i
b
where
a creep rate of the non-synchronous belt is denoted “γ”; a ratio of pitch diameter of the crankshaft pulley to pitch diameter of the input shaft pulley is denoted “ψ”; and a ratio of the angular velocity of the crankshaft to the angular velocity of the input shaft is denoted “co” which is characterized by the equation
ϕ
=
ψ
1
-
γ
and where
a gear ratio denoted “i b ” of the planetary gear train is characterized by the equation
i
b
=
N
S
1
·
N
P
2
N
S
2
·
N
P
1
where
N S1 , N S2 =number of teeth for the first and second sun gears respectively; and
N P1 , N P2 =number of teeth for the first and second gear ends respectively.
15 . The method of claim 13 wherein controlling the motor comprises commanding the motor to control the planetary gear train such that the angular speed of the carrier ω C is controlled to maintain a relationship with the angular speed of the output shaft ω S2 according to the equation:
ω
C
ω
S
2
=
ϕ
-
2
i
b
ϕ
-
ϕ
·
i
b
where
a creep rate of the non-synchronous belt is denoted “γ”; a ratio of pitch diameter of the crankshaft pulley to pitch diameter of the input shaft pulley is denoted “ψ”; and a ratio of the angular velocity of the crankshaft to the angular velocity of the input shaft is denoted “φ” which is characterized by the equation
ϕ
=
ψ
1
-
γ
and where
a gear ratio denoted “i b ” of the planetary gear train is characterized by the equation
i
b
=
N
S
1
·
N
P
2
N
S
2
·
N
P
1
where
N S1 , N S2 =number of teeth for the first and second sun gears respectively; and
N P1 , N P2 =number of teeth for the first and second gear ends respectively.
16 . In an internal combustion engine, a method of controlling a phase shift angle between a camshaft and a crankshaft of an internal combustion engine, the method comprising:
connecting a non-synchronous belt to the crankshaft and to an input shaft having a first sun gear end coupled to an end of the input shaft; aligning a planetary gear train around the input shaft and around an output shaft coupled to the camshaft, the output shaft having a second sun gear coupled to an end of the output shaft; meshing a first planet gear of the planetary gear train with the first sun gear and meshing a second planet gear of the planetary gear train with the second sun gear, the first and second planet gears being united to rotate about a common axis through a carrier of the planetary gear train; operatively connecting a motor to the carrier; receiving an angular position signal of the camshaft; comparing the camshaft pahse signal signal to a reference signal provided by an engine control unit; and generating a torque command signal based on the compared camshaft signal wherein the torque command signal commands the motor to adjust the phase shift angle between the camshaft and the crankshaft.
17 . The method of claim 16 wherein the torque command signal is denoted “T ffwd ” and is determined according to the equation
T ffwd =T rq — static +T rq — friciton =(1 −i b )· T cam +sgn( v )· f ( T cam ) where T rq — static is calculated from a frictionless static equilibrium condition of the three-branch gear drive; T rq — friction is a component required to overcome frictional torque for current camshaft torque load; T cam =the camshaft torque load; and f(T cam )=magnitude of T rq — friction .Cited by (0)
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